This guy added me on Facebook, and i don't even really kno him... why did this happen?

So he added, me and i've never seen him in school b4 but i decided to add him cause he seemed pretty cute in the yr book. On his prof. it said he was single and looking for a relationship right? so he had his sn, email, and cell posted up. I put his cell in mine and i txt him. I was debating weather or not too but i wanted to see what he would say. So he said 'well it is kinda weird that ive never met, or seen u b4 and u txt me...' i agreed with him long b4 he said that, then he figured out i liked him cause i said their was another reason y i txt him and he said 'cause im hot'. and then after a while he said 'will u plz stop talking to me?' y would he b like that... when it seemed like he was being nice. he was the one who added me, was it that big a deal? now hhe wont get back to me and i sent him an e too. i was just trying to b nicee. Why do guys always act like that.... it kinda bugs me and pisses me off.!