No, this isn't an invitation to have an idealogical debate about vegetarianism... although that's how this matter came up for me.

Where did the phrase "what's your beef" come from? How did it get from being 'the flesh of a slaughtered full-grown steer, bull, ox, or cow' to being something which is obviously an "issue"?

I'm un-motivated to go looking for answers elsewhere, so I thought I'd pose this to y'all wise and learned ones from all over the world. So sue me.