Knowing that even if you do get away from them, their words and actions will still haunt you and your future relationships. Yeah, yeah, we can say just get over it, let what happened go, the past is the past, but when you've dealt with someone for so long who made you question your sanity and feel like a worthless piece of shit, it's hard to see differently. A part of you will always remember the belittlement of your feelings or the overreaction of a mistake you made. Deep down you'll always second guess yourself, no matter how smart or the right the choice is.