The two faces of one person

How is it that one person can have different faces and you can see them change multiple times in a span of an hour. A friend of mine was sick this weekend and every time he was weak he was all needy and wanted me around and then the moment he felt slightly better, he was back to being an assh***. It's unbelievable but in 5min he changed from hug me, I am so weak to why are you here, I don't even want to talk to you. Maybe it's just that one individual because I would assume that most normal people would be thankful that someone was out there when they were sick and wanted to make them feel better. I guess the next time the person calls me sick, I will not be around because I don't want to interact with someone, who is only nice on an as need basis.