Freaky customers

So, my friend was serving this crazy-eyed smelly (sorry but I have to be descriptive) poorly dressed Maori man about 30-45 aged. Well it was hard to tell his age, he was so...
anyway

He asks for a leg piece. (This is KFC by the way.)
So my friend tells me to pack him a thigh, which is better/bigger than a drumstick. So I do, and give it to him.
He tears open the box, points out that 'no, no, this is the wrong piece, I asked for the LEG piece, the LEG piece'.
'You mean the drumstick?'
'Yeah that one! the LEG.'
So I go and get him a drumstick instead. with my back turned to him while putting it in the box, and my friend standing there,
he starts yelling and cursing angrily.
'huh! Stupid! F***ing can't do your job! F***ing Chinamen! F***ing can't even do the job properly, F***ing go back to their own country, F***ing **** ******* *****! F***ing give me the wrong piece! F***ing stupid!' (Something along the lines of that.)

Now, as one would expect, all the other workers, including the manager, comes and watches, and the manager asks
'Is there a problem?'
And he rants again.
I was too scared to give him the drumstick. I thought he was going to kill me or something.
But I inched forward and did, because customer service is important, no matter how abnormal they are.
He grabs it, continues yelling and swearing incoherently, eventually leaves the store, still muttering angrily, (you should have seen his eyes - like a madman indeed,) and I'm pretty sure he threw the box liner thing in the air while he was outside, as a final act of rage. Well.

It truly shook me, that experience, the manager said 'are you guys alright? far, I'm too scared to leave now!' (she was going to go out back to do something), and I was in a bit of shock. My friend reassured me that 'doesn't happen often.' Thank bliddy heavens.

By the way:
did he have to litter?