Boyfriends mind/games

What goes on in a guys mind. What does it mean if they talk to you and you get no further reply but they give you an answer an just walk away and they act like nothing even happened.. Seriously they come back all lovey-dovey and is seemed like that conversation never ever existed. Are we supposed to know the answer to the question already or are we supposed to just forget this fucking conversation never happened. CoNFuSEd