One guy, who very drunkenly threw a punch at a friend (and missed) for unknowingly taking his chair even told us that his mother had just died and he only went out to the bar to punch somebody.

But, yes, bar fights still happen regularly.

That said, my experience is:

  1. They are somewhat cultural.  More common in some regions/bars/demographics

  2. They happen more frequently as the night/drinking deepens

Where are you going to find regular bar fights? Is it more a US thing, a rural thing, a college town thing? Because despite having spent way too much time in bars in various parts of Europe, I've basically never seen anything escalate beyond shoving and shouting.

I last saw a bar fight on the north shore of Kauai. I love Kauai, but locals have told me, "there's not much else to do at night other than drink and fight."

In some places, drinking is just something that do you do when you go out, in others, it seems like drinking is the goal of going out and they try to get drunk the faster the better.