A slap can simply be a symbolic thing, with no real intent to do anything other than act as a rebuke and cause some embarrassment. Or, it can have some effort behind it, with the intention of causing physical discomfort. It's difficult to tell which category this guy's wife falls into from watching that video.
But I interpret that video clip as demonstrating one of those two types. What she did could not realistically be thought of as starting a physical fight, and was by no means anything that would merit a man..."professional" fighter or not...actually retaliating...let alone going in for a second shot at her.
One must wonder how that little exchange would have escalated if it had occurred out in the parking lot, with no cameras around and nobody to step in and separate them.
I'd say alcohol is the major trigger in most cases though. Like you said, it turns ********s into even bigger ********s.
The term "trigger" is very appropriate for this. And a trigger is only dangerous when it is attached to a gun that is loaded and cocked. The trigger simply lets someone unleash that dangerous potential; without the actions of a person, the gun itself is harmless.
Things get bad quickly if the trigger...whether a metal lever on a gun, or a bottle of booze...is activated by the wrong person.
