This should concern you much more than her not liking John Mac. You may be in early stages of courtship now such that she is hesitant, but if you are even remotely moving toward marraige [which incidentally, you should be moving that direction eventually, or else break up with her...but that's another discussion], She will have to be willing to talk to you about the real reasons why she does things, or likes things, or doesn't like them...otherwise a month after you're married she will be really mad at you...but she won't tell you why because she's scared of offending you.