Not sure why someone would just flip like that instead of politely replying

He must have had a really bad day but that’s no excuse for that kind of violence behavior.

He’s the kind of jackass that we need to be necessarily rude too. Someone ever shoves me, I’ll be sure to shove back.

Probably thought the employee was “customer service-ing” him under the suspicion that he was trying to steal. He could have had that happen to him on more than one occasion and he finally had enough of it.

Just leave him be like he said

Nu-uh. Unacceptable behavior. I hope your manager kicked him out.

I sure hope you reported to your manager and called the police. Battery is illegal.

Criminal Battery and possibly Assault depending on what your state statute says. Next time someone shoves you I'd get law enforcement involved, there's no reason to become physical over a mere question no matter how your day is going or what the question is. Play stupid games win stupid prizes.

personal space, man. learn it

And that's assault. Check the store security cameras (if there are any) and file a complaint.