My deal breaking behavior WAS cribbing... until a mare I bought turned out to be a mild cribber. She only cribs on plastic after she's eaten and still wants more; she doesn't crib at all in pasture. It hasn't gotten any worse, and the other horses haven't caught on, so I figure I can deal with it... plus I love her to bits.

I can't stand pushy horses who try to run me over when I lead.