I'm continually surprised and confounded by what peoples preferences end up being. At this point I've pretty much given up guessing what any one person or even most groups of people will actually like because I'm pretty much wrong most of the time.
Had another interesting reminder of this last week. When I get free wood from someone for <whatever> (usually turning) I try to give them first choice of the resulting product. Yields pretty good return-on-wood as far as getting more goes. I took the sweet gum bowls I recently finished over to the woods source for the fellow to pick out his bowl (from this set):
I was virtually certain he was going to pick one of the cauldron/vase shapes because he's a huge gamer and it would fit in with the decor pretty well. In the end after some discussion between him and his GF it was between the two in the lower left of the photo which is interesting because although I like the smaller one, its the smallest of the set and the one next to it was my least favorite, its whiter and more "plastic" looking (I was playing around with different finishing techniques - straight WTF on sweet gum doesn't do much for me).
They ended up picking the very smallest one (9" x 3" - 3/8" wall so not tiny but not huge either).
Justification on the size was that they "wanted something they could use" and that most of the pieces where "to larger to be generally useful" - makes sense.
Also interesting BOTH bowls that they picked for choices had "flaws" in them where there was a bit of a bark inclusion. This has been a fairly common trend where folks will pick up a natural edge bowl or a bowl with some sort of knot or worm holes or bark inclusion in it before they'll pick up anything else.
Anyway - just thought that was interesting.
What have you run into that confounded your expectations of what customers would want to see?