Who was this guy and why so serious?

my first language isn't english, and at least according to my teacher, "Break a leg" expression is used for "Good luck". But I was invited to a indy event a couple of years ago (2 or 3), and told a young wrestler ("Owen" something I think. Can't remember his name) to "break a leg". The guy looked at me and I guess he took it too literal because he put a mad face and almost killed me with the look. Who was that idiot and why do wrestlers take thinks so literally? From what I understand, its a common expression!!!