I have a problem, whenever I change from creative to survival mode, it wont let me interact with mobs, I cant attack them nor feed them.
In creative mode the mobs are set to basically ignore you. (nobody wants a creeper messing up there creative mojo.) They will only notice you or engage with you if you touch them in some way. (note: not sure if just looking at an enderman will set him off in creative. you may have to touch them as well)
Hope this helps.