You become food for worms and maggots.

Your bodily fluids replenish nearby plants.

Your body decomposes and becomes new top soil.

If your cremated none of the above. You just poof in a cloud of smoke.

If your buried in a casket who knows how long your remains will be in it before it is destroyed. Who knows what the decomposition rate of a funeral casket is these days. At any rate in a casket I imagine your body might be mummified if it was air tight but then again if wasn't air tight you just would be left with a funeral suit and skeletal bones overtime.

That's why I think you should look fantastic and sauve on your final last day so if somebody digs you up they will say to themselves that skeleton is wearing a really nice suit.

Believing in a afterlife is humans vain attempt at making themselves seperate and different from other animals or other living things making themselves believe that the universe has a special place in reserve for them while giving themselves a false sense of self privilege.

That right there is the basis of all religion.

It's the ultimate form of vanity as it is the ultimate form of self worship.