(Spoilerific, obviously)
My paragon vanguard romanced Tali, obtained all loyalties, entrusted Legion with the vent job, put Miranda in charge of the fire team, Jack on Huge Biotic Bubble duty and lost no team members except for Yeoman Chambers, but I privately dedicated the last mini-nuke I shot into the Larvae's chest to her. Retribution makes big boom. I preserved the Collector base (for science!) and felt no compunction about terminating my working relationship with Cerberus. TIM seemed just a bit too eager to have his own Reaper neo-natal station.
That was that, I thought. Cerberus has all the tech they could possibly need to fight back against the inevitable invasion from Dark Space, I have the smugness of knowing that I'd taken the moral high ground while delivering a sound thrashing to The Big Bad. Day, saved. Unstoppable and fiercely loyal private army, assembled. Quarian hottie homegirl, satisfied. (Not to mention social life, neglected.) I proceeded to take a bit of a victory lap around the Normandy, to have a final chat with my crew members and generally bask in the reflected glow of my own awesomeness. Egotistic? Probably, but dammit, I'd earned it.
At this point, I noticed a common theme in all the conversations that emerged. Everyone expressed variations on relief, triumph, etc with a general sense of "We did it! Huzzah!" (I particularly enjoyed Tali's assessment of "Worth it"). However, without exception, each squad member's P.S. came with an emotional tone I had not expected: subtle doubt. The consensus was that we would be able to kick the ass (entry port?, I don't know) of any Reaper that dared mess with our galaxy. Despite this, I lost count of how many of my people simultaneously expressed faith in my capacity to lead them to victory, and fear for what TIM might do with his newfound Build-a-Reaper toolkit.
Had I won the battle, but laid the groundwork for the emergence of an even greater threat, one spearheaded by a xenophobic and power-hungry bastard who justifies the atrocities committed by his organization under a guise of Machiavellian pragmatism? Would I have to defend sapient life from a war on two fronts, as our bodies faced annihilation (or worse) from the edges of habitable space while a tyrant plotted the subjugation of all life under the heel of his own private human empire? Can a human impregnate a quarian? ME3 has many questions to answer, and I STILL need to take that original character into the Lair of the Shadow Broker. Earth = fucked.