Here's an unusual furniture piece from South-Korea-based industrial designer Donghwan Song: The Tamable Chair, which is made from the unlikely material of Styrofoam. In the spirit of experimentation, Song played around with the material in a variety of profiles.
Styrofoam of course deforms under pressure; thus Song intentionally chose a profile liable to make deformation obvious.
The idea is that the chair becomes "gradually optimized" the more you sit on it.
I suppose the flaw is that it assumes just one person will use the chair, and that the user always sits in the same position. Not to mention: Wouldn't using this lead to you having little white dots static-clinging to everything in the vicinity?
I can't deny, however, that I'd be super curious to try one of these, just to see what shape it settles into after a month.