Crazy people are fun until they do you wrong agree?

Obviously

My ex girlfriends

Crazy is such a huge umbrella under which various kinds of people would fall under and not all of them would be a problem as such.
But there are some people who become dangerous in various degrees for something perceptually done to them.

Narcissists can be great to be around until they don't need you or are threatened by you.

If you know someone is crazy where is the surprise?

If you’re crazier than they are it won’t be an issue.