You hit on his girl. You spilled a drink on his shirt. The economy. Whatever the reason, you’ve got a screaming match on your hands- and the guy is a lot bigger than you. Well the first thing you should try to do is avoid the fight to begin with. Unless you know you can fight, you can get seriously hurt or even killed by messing with the wrong guy. Especially that everyone and their mother trains in an MMA gym now.
-So reason with the guy.
-Divert his attention- “Oh my bad for stepping on your feet, damn those are nice shoes, are they Bally?”
-Offer to get him a replacement beer. $5 bucks and your pride are not worth a night in the hospital.
Now if none of those work and he’s still livid from hell to high water. You can either sucker punch him while his jaw is yapping as hard as you can and hope you knock him out, perform a flying arm bar, or weather the storm.
Standing with your arms folded scratching your chin does not signal that you are willing to fight. But in case he throws a haymaker your arm is up and ready to block and deliver a devastating counter elbow to the jaw.
Then when he’s on the ground peacefully sleeping, you can down your beer, grab your coat and casually walk out.