If a girl is attaching me with a knife and I fell my life is in danger, damn right I would do anything in my power to defend myself, but what some people are talking about here is the scenario were the moment a girl hits a guy all bets are off and an upper cut is granted, to me that is cowerly behavior and I would respect a guy that would walk away than a guy that decides to 'teach them a lesson'
Yup, I think Newton's third law, or some appropriate application of it, should apply.
Now I am out.
Me too. Nice chatting with you.