Biceps - hard to develop them on/off.
Maybe i simply don't like the shape and structure of the muscles. There are Chihuahuas with more developed front legs than my biceps.
IMHO this has more to do with the cards that we are handed at birth. Look at your parents, and look at your ancestors for prime examples. Henceforth, our genetic predisposition plays a huge part, as much as we try to overcome it with the use of hormones. Always had chest, shoulders, traps - even the legs like i was juiced to the gills, then the arms show up and the game is over. It looks like i never touched a weight.