If you just punch a dude in the face, will it start a nonlethal fight or will it go into a sword drawing fight? Maybe it is like the Witcher 2 (haven't played that game but from previews..) where there are a group of ugly, hairy guys in the corner that ask to fight.
Personally i want to be able to fight anyone at the bar, not just the people in the "corner".

I was wondering this as well. I can't wait to get into a bar fight

It starts by you eyeing that sketchy looking Nord's wife while he's in the outhouse.

The usual. You get drunk. You throw a bottle into the head of somebody. And more flying things comes next.

It starts when you stick your tongue in the ear of that busty blond wench from the screenshot.
You know the one i mean..

What ye doin' hea? zismsvmvgtbkhjgfdd to vcparty........./vomitsonwench

It comes when you least expect it.

The Nord at the end of the table buys a drink for you because he likes your face. A few rounds later, he starts a fist fight with you because he doesn't like your face.

Punch some random guy in the face.

Everyone should my face!

Could start by telling someone that their mother is a hamster and their father smells of elderberries.

NPC stealing food and eating it.

Blonde* Blond refers to males.

Unless you meant a blond guy... then yeah i'm sure if you stuck your tongue in the ear of some blond nord it would start a barfight. Infact sticking you tongue in anyones ear is pretty creepy.