I had a SIL (had being the operative word) that literally had me seeing red. Yes the saying is true, you can get so angry you see red. If I ever was going to do bodily harm to anyone, it would have been her. In fact I had her backed in a corner once and it took my mom, dad and DH to pull me off and I'm not a physical person. I would much rather use my mouth unusual words to tell someone off and even then I have to be really pushed.