What are the wrong reasons to get in a relationship?

When i say wrong reasons, I mean wrong as in for example if a guy wants to be in a relationship just for sex, then its not real relationship. The whole thing is a complete time waster except for the sex of course. But the rest outside of sex of the time being spent on something fake. Just for the sex would seem like the top wrong reason, but i know theres got to be different reasons too. So what the other reasons? What if one is just getting in a relationship just for attention or he wants the girl to be all about him? Wrong reason? and if so, alittle explanation on that.