Why are guys mean even i haven't ever even met them?

there is this one guy at school who came up 2 me an my friens and (boy friend) ...an picked me out of everyone an started using horrible pick up lines and actin awful to me. and my friends (mostly me)..and of course i told them 2 leave.now a few months later after they finally stopped bugging me (did it almost daily for a month)....they start in again being perv's and really mean....i don't act slutty my clothes are proper an im shy (till u make me mad) ...and it really hurts because iv never even done anything to them