Just be smart enough to know when "enough is enough".You can't complain about about somebody crossing the line if you fail to set the boundaries. You can't complain about somebody wasting your time when you didn't require them to earn it. Sometimes you just have to let go. Not everything is meant to be a forever kind of thing . You have to be honest with yourself even if it hurts. You can't give people too many chances to make the same mistakes.
Learn from it.
Grow out of it.
Be done with it . 
:)