i love the theory that the ending is in fact fake as it is an atempt by harbinger to indoctrinate both shepard and the player.
this might come off as crazy or fanboyish or simple denying that the ending sucked but it doesn't matter because it's a compelling theory
first let's examine the little boy shepard sees throughout the the game. is he even real ? we see in the beginning of the game a little boy playing with a toy inside the alliance compound maybe a bit strange for a child to be there but nothing out of the ordenary. later when the reapers are starting to land we see the child running in to a building which is promptly blown up by a reaper. as we enter the building shepard notices the child hiding in a ventilation shaft.
the kid says something rather strange for a boy his age: "You can't help me" in the following moments shepard tries to help but hears a reaper behind him and when he looks in the shaft again he sees that the boy is gone. also notice the danger of electrocution sign next the the shaft. Anderson doesn't seem to notice that shepard saw that kid and shepard doesn't say anything about it as well.
later when shepard is about to leave on the normandy we see the child climbing in to a transport which gets blown out of the sky making it once and for all clear the kid died. but strangly during the whole time no one but shepard aknowledges the kid or tries to help him.on the citadel we can see a picture of the boy at the memorial wall in the refugee area of the citadel. when shepard first returns to the ship after getting shafted by the council he experiences a dream. we see a desolate forest and the kid running in the distance shepard tries to run towards the kid and as he gets closer we see the kid going up in flames.
as the game progresses shepard starts to lose (a bit of) hope of making it through even as he unites the galaxy we can see the war take it's toll on shepard; as he experiences more dreams we can see the dead starting to appear we hear the voices of the companions we've lost in the war and see "oily" shadows and hear voices.
just before the attack on the cerberus base shepard has one final dream filled with shadows and voices ending with shepard seeing himself embrace the boy and with a rather creepy smile going up in flames alongside the boy. all of this is rather strange and after the dream shepard is irratable and confused.
in the final assault where everyone is trying to get to the conduit (ME 1 anyone?) harbinger finally shows up and starts lasering everything in sight including shepard. when we see him "wake up" (this is the part where the indoctrination becomes reality) we see harby flying away and shepard getting up in a wasteland with corpses all around. depending on your EMS score we can see our companions lying dead or not (higher score = we don't see them) and on the left we can see the same kind of trees that were visible in the strange dreams.
as a player we can't pan the camera down to see our feet and we get a gun with unlimited bullets. we see mountains of corpses lying around the conduit and as we walk towards the conduit husks and a marauder apears (sometimes only the marauder,I asume it depends on difficulty or EMS don't know for sure yet). shepard walks faster than his/her animation would suggest but also still very slow like in the dreams. also just like in the dreams the surroundings are a bit blurred.
shep steps on to the conduit and is teleported to a new part of the citadel. we hear anderson on the comm and shepard reacts and speaks without pressing his ear (what you see him do in most of the game when he comunicates with someone over the comm). again we see a lot of corpses all of which bald and with a doll like appearance. we see two keepers both of which are typing on nothing but air.
Anderson says the place looks just like how shepard described the collector base and shepard agrees even when this is not the case. Anderson mentions shifting walls shepard then walks through a doorway and comes acros the chasm to see anderson standing in front of a console. the strange thing about that is shepard was in front of Anderson when the race to the conduit began. also Anderson seemed completely unharmed. we also hear cole mention that everyone was wiped out by harby would two people going in to the not conduit stand out ?
we then see TIM enter the scene he looks like a half transformed husk and starts trying to convince shepard that control is the best option for humanity. he uses arguements strangly similar to saren at the end of mass effect 1. parralel to the ending of ME 1 as a pure paragon and having chosen the paragon option throughout the game (specifically to TIM) we can persuade TIM to break trough the indoctrination and shoot himself but not before shepard shoots anderson in his belly.Shepard then opens the citadel so the crussible can link up.
we see a scene where anderson and shepard talk ending in the death of anderson. shepard then hears hacket over the comm and shepard again talks back wothout pressing his ear. but before shep can reach the console he passes out interestingly he cluches his belly right on the spot where he shot anderson and andrtson didn't seem to be hurt at all by the shot. one thing to note was in the enviroment where supposidly no organics had come there is a structure that was also seen on the shadow brokers ship with the code 1m1 on it. this is strange because why would a otherwise clean enviroment (as in no descernable structures or text) have that in it. also 1m1 is used in a formula in optics for convergance and in a logical statement means that something will always lead to the same outcome no matter what.
we see shepard being lifted up or "ascending" as it where to the exterior of the citadel. there he is greeted by the boy we see in the beginning and the dreams. he introduces himself as the catalyst depending on EMS again we see a differance. his behaviour changes when you have a low score the boy says: "what are you doing here" on higher scores he says: "wake up".we never get to know why the catalyst just happens to look like the kid. shep asks if the catalyst knows how to defeat the reapers. the catalyst then explaines his BS solution to the organic synthetic conflict. and offers three solutions (two if you score lower or even one in the absolute worst case scenarios) the first is the destroy ending this will nuke the reapers but also (acording to the catalyst) the geth and edi and even shep himself will die and he implies this choice is bad don't go for it.
the Second choice is control he tries to appeal to shepard's pride saying do you think you can control us ? he makes it clear shepard will die but will also control a very paradoxical answer. and finally synthesis the best solution i mean it's green and it takes more effort to achieve at all then the red or blue ending. this is to both indicate to shepard and the player that it is most def the best choice. shepard can't really argue with the catalyst so the player is forced to make a choice. in the confusing moments that follow we can see the three coloured endings which by now must have been burned into the brains of every hater and lover of mass effect and generally leave a bad taste in everyones mouths.
what i haven't expanded upon is that when you read the codex entry for indoctrination : http://www.youtube.com/watch?v=MrTgXu0UjCg it becomes earily clear that these things are happening to commander shepard. he sees and hears dead people (albeit in dreams) also describable as alien voices, he can possibly kill the VS, he can choose not to renegade interupt Kai Leng or Udina al pointing towards subtle hints of indoctrination (of both shep and the player to learned ME behaviour). it is left ambiguous if the prothean vi recognizes Kai Leng or Shepard being indoctrinated. the VS asks on mars if you would know if you are being controlled and later on the geth virtual reality mision joker asks if you know if you are in realtiy again. i see these as subtle hints (perhaps i look to much into them but still) to indoctrination.
but let's get into the stuff that makes it really weird shall we

. when listening to the catalyst we hear three voices: the kid and man an femshep. in the line: "you have more hope than you think" hale's voice emphasises the word think (not to shep but the player). when the choises are presented the destroy ending resembles Anderson but the choice is red indicating a divergence in wheter you should believe anderson is doing a renegade thing, or the colours are intentionaly mixed with the parralel blue ending where we see TIM. note that throughout the game Anderson,Hacket and Shep decide that destroying the reapers is the only solution; to cooperate is to die. note how the blue and green choises are brighter choices than the red one. also see how controll looks like a reaper structure and red like an alliance one.
When choosing either control or synthesis we see shep disintegrating but just before he is gone we see what looks like a husk of commander sheppard also note the TIM eyes on the control ending. and think about it; TIM represents the blue control choice, Saren represents the green choice and Anderson represents the red choice. why does Saren represent the green choice ? because if you listen to saren's speech at the end of ME 1 you clearly hear him talking about being synthetic and flesh, organic and steel and being with sovereign is teh awesome.
what do these choices really represent then ? i see it as blue you become a husk as you try to control a force much greater then yourself. green you become either a sleeper agent or saren like imitation because you gave in to the will of the reapers (notice how shepard accepts the ending by jumping into a beam like surrenderingto it) and red you fight of indoctrination it is the only ending where you have to use violence to achieve it. one of the main reasons to support the idea that red means fighting indoctrination is the fact that you need 4000-5000 EMS to get to see a small clip where shepard is lying under what appear to be concrete rubble and takes a surprised breath. what does it actually do then and wtf is up with joker flying the normandy in the middle of nowhere to crash on some random planet ?
in my explanation a lot of the ending is metaphysical or rather an interpretation to the player to see the internal struggle of commander shepard trying to fight of indoctrination before he eiter dies/becomes indoctrinated or lives during this whole time he remains on earth just meters away from the conduit. the crucible firing is the final heartbeat of commander shepard before the end and the normandy crashing on a random planet are shepard's last thoughts about his best friends somehow surviving whatever he happens to choose. it's funny how crucible can mean a very though test or challenge and maybe it means bioware is testing the resolve of players to have shepard stick to his resolve to kill the reapers even at the possible cost of genocide and murder (possibly suicide).
also funny is how the only way to get to the scene where shepard is alive and breathes in is to choose the option that the catalyst insists will kill you also this plays after the crash landing implying that none of it happened. as everyone has pointed out in numerous threads on the webs; the current endings feel wrong, too short and fake. the reality might be that bioware is trolling everyone with this ending and the true ending is yet to come as a(possiblly at cost) dlc or a patch.
it could also mean i need to get some sleep before i make my post any longer than it allready is. please excuse any and all gramatical errors as english is not my native language and i'm very tired right now.