Extremely particular, fussy, or choosy. My son was such a picky eater as a kid that at one point the only thing he would eat was white bread and sliced bananas—nothing else.Stop being so picky—one brand is as good as another!
picky
1. mod. choosy. Red, blue, green! What’s the difference? You are too picky.
2. mod. overly critical. I have to do it exactly right. My boss is very picky.