Preference like not smoking and eating vegetables are just some of the things that I would want for a person since I really can not breath when some one smokes a cigarette and that I am fond of eating vegetables. There was one of my admirer before, who really could not eat vegetables. It was not a big problem for me, but somehow, I could not ask him to eat vegetables.
But sometimes, being strict on your preference makes you not see the right person for you. Or in some cases, when that person fits to your preferences, then you would think he/she is the one but really not.
When having a preference is not bad, sticking to it too much is some what likely bad. Be open and enjoy being with some one. If you feel at home with that some one, then maybe he/she is that one for you.