Why did he unfriend me on FB for no reason?!!!!! (please answer)?

[DoubtBox]

well,there is this guy from my college ,same year but different class,but we both know each other well because we have mutual friends though we never spoke to each other personally.....he sent me a friend request yesterday and i accepted it....then he started the conversation first and started chatting with me for quite 2 hours,he was really into the conversation and it seemed he enjoyed chatting with me,he also used a lot of smileys and it looked like he was flirting,and i was playing the same way,i wasn't boring or anything,we both really enjoyed it,then we said goodbyes to each other.
And then today when i checked FB he unfriend me...but what's the reason,that was pointless,why would he do that?...please help me!!!
don't freak out guys,i just asked it again to get more appropriate answers and did u answer answer it earlier to say that?!