I don't think people should change the way they behave out of fear or out of what someone else would think of you. So what if they are interested in you and you're not. It's bound to happen no matter what you say or do. Attraction isn't something someone chooses. Doesn't mean that you have to like them the same way back and it certainly isn't your fault, if they have a problem with you not liking them that is their problem and they'll have to learn to accept that.