Do you think that everything L says is a lie?

L is very secretive, and when he said that he didn't suspect Light as Kira all the times he was lying. How do we know if the personality he's brought up in Death Note is just a fake? He may have pretending to like sweets, sit in an odd way, and hunch over, maybe at heart he's just like Light. I mean L and Light are very similar, anyways. And if you read the one-shot, it said that he doesn't really care about justice, he was just bored. That's the strange thing about L, you don't know what's real what's not. He said himself that "he is a monster that lies."