"His/her entire life was pointless. Accomplished nothing of note. The world will not mourn, or even notice for a tenth of a billionth of a trillionth of a microsecond. This funeral is utterly insignificant, for his/her death signified nothing. Not the closing of an age or the start of a new one. The only people who cared even remotely about him are the few crammed in this small room, and half of them are only here because they think it's polite to do so. Not only that, you suckers spent thousands of dollars on a coffin for a corpse that cannot possibly care or enjoy the fact that it is being buried in pine instead of, say, balsa wood. Should have probably bought the balsa wood coffin. Hell, should have just stuck him/her in the ground and let him/her fertilize the soil.
Anywho, to wrap things up - this funeral is just one of no doubt tens of thousands which are being held around the world this week. Think about it, the most painful, horrible moment to you, is nothing, I repeat NOTHING to anyone else and really, the rest of the world doesn't care. And no, your special someone wasn't all that special. Was he or she an astronaut? A nobel prize winning scientist? Head of State? A great, renowned artist? Didn't think so. I'll level with you, there are and will be hundreds of thousands of people JUST LIKE THE PERSON IN THE BOX.
And while you stare at the corpse sitting in a very expensive box that it can't enjoy, whilst the funeral director gets a couple thousand bucks for saying nice things and planning "where the body goes", I'd like to remind you that, you too, will be here and once all your immediate family and friends die, the world will completely, utterly and TOTALLY forget your existence. Like stiff here in the box, you could not have been born, and no one, NO ONE would have noticed or given a damn.
There's a few snacks on the table to your right, we'll put the old geezer in the ground at noon..... and I'm outta here. Suckers!"
And that is the absolute worst thing you can ever say at a funeral.