What are some reasons for some1 not to tell you they like you?

Let's say your crush also likes you as well. You have no bf, you're friendly, nice, intelligent, attractive, and etc... there's nothing wrong. What are some reason he may not want to tell you he likes you? I just don't get him!!! who last 3 years without telling their crush that they like you??it was junior year where i actually found out he liked me cuz his closest friends told me he liked me since 9th grade. Then i fell for him for all the things he did to grab my attention... in junior year. Why can't he tell me? I know u may bhe wondering why i can't tell him but im TOO SHY!!!! why can't he toughen up a bit?! XD I already wnat somethign between us this next school year.