jesus, i never said that short guys look stupid, either.
My point is that passing is subjective. One may pass at home on one's couch, but not at all when compared of the same sex. Height and stature in general doesn't help. Small hands, small feet, short, thin limbs. Sorry, but when/if people question you that's what they look for.
In one of those Ultimate Survival Guide to Life books, there's a whole list of things to look for to ascertain the gender of your date. Comical, but accurate.
On a personal note, if I didn't feel I could pass well and assimilate into the male population, I wouldn't have transitioned.