Well I suppose my friend is an ISFP and here are a few traits that bother me about her:
1. Avoidance, denial of negative feelings. "Put on a happy face 24/7"(PS: she can hate your guts deeply and will never show it. ._.' )
2. She has this laid back attitude that is sometimes borderline laziness.
3. She acts like an idiot, a helpless defenseless girl to get people to lower their defenses but could probably get to them easily if she wanted. (ISFPs are not harmless, nobody is)
STOP acting like a victim! If you can withstand such crap then you're probably tougher than you guys think.(Also, they use the number 3 to get people to do things for them sometimes -.-)
4. She whines about many things that are wrong with her life but doesn't do anything about it...(see number 2.)PS: They are things she could easily fix if she took time to do them.
(From my own limited personal experience. Might not apply to all ISFPs)