"This is why I run. 

Because caring was a thing with claws.  It sank them in, and didn't let go.  Caring hurt more than a knife to the leg, more than a few broken ribs, more than anything that bled or broke and healed again.  Caring didn't break you clean.  It was a bone that didn't set, a cut that wouldn't close."
-A Darker Shade of Magic by V.E. Schwab