I'm pretty sure that, working or not, what that guy did was assault and thus illegal. I suggest looking into it, especially since he could have seriously hurt you or anyone else he got it on.

It sucks and was 100% uncalled for and that customer is a jerk. But, at least, the barista wasn't at risk of getting burned as the drink in question was likely kids temp. I hate rude customers. Maybe he should have actually looked at the drink name.

Battery, actually, which is worse. Assault is essentially the threat or implication of violence where reasonable means to carry it out exists. Battery is any form of unwanted and/or destructive physical contact, by body or by proxy, where consent has been declined or can be reasonably assumed to be.
OP, furthermore, not only does the fact that you were on the job have no mitigating effect on the penalties (unless your employer has some kind of bullshit waiver), quite the opposite; most courts have harsher penalties for people who attack and disrupt people where they work.
Tl;Dr, that person attacked you physically; you could have their head in court.

What was the costumer wearing, I wonder?

You should have ratted out the customer to the boy. "That bad man stole your chocolate -- go punch him in the balls!"

I don't understand how someone can get so mad that they pour a hot drink on another person. That's so disrespectful. I hope that your manager did something about it.

They probably fired OP, considering how FMLs tend to go

In this case, it was likely a warm drink because it was for a four year old. But, still, he never should have thrown the drink at the barista.

That's more than disrespectful, it's assault.

I worked at Starbucks and that happened to me
I got workers compensation
You should really look into that
No one should be treated like that
I hope that guy was embarrassed
Plus how vain of him to think every drink with that name is his

I hope the guy was arrested.

What an asshole. He was evidently too stupid to realize it may be for someone else, and even if it was for him and was wrong, that was still fucking uncalled for. I hope your manager saw this. Sad day when you have a grown up act worse than a 4 year old.

If this happens to anybody please call the police if you had the self-restraint not to beat them down.

Please follow up on this.

Basically, fuck that guy (not literally).

People like that make my blood boil.

Do the workers call out the order as well as the name? Like "hot chocolate for Michelle" or something or is that not every cafe

A lot of them only say the name, especially if they're busy. It usually says the order on the side, either written or with a the ticket stuck to the side. I always check that, especially if they only say the names.

I'll always say "[drink] for [name]" even if we're busy.