I'll try to make this short and sweet...but good luck to me.
1. My first experience was as a bar back at a dark lounge in Austin.
A guy started slamming his crying girlfriend against the bar and against the wall to the bar. I jumped over and grabbed the woman and pulled her behind the bar as he started slapping her.
At that point the HUGE dude grabbed me and started throwing blows. As I looked up the only thing I could see was the trail of cocaine going down his nostrils.
Sadly she started hitting me too while crying hysterically.
Luckily my bartenders jumped over the bar and it took all three of us to move him to the door. At which point he told myself and another that he'd be back at close to kill us. I stayed in bar till five am staring out the windows slats.
2. Same bar, I had a guy come out of the bathroom completely naked and started screaming, "Everyone, lets fuck!!"
The bartenders laughed and told me it was my job to escort him out since I was the barback. So I grabbed the doorman and we went to confront naked guy. He stood spinning in circles and tried to explain all he wanted to do was, "start an orgy cause there's lots of beautiful people."
When we asked him to leave he punched the doorman in the face. Needless to say... we beat up a naked guy. When the police came they asked us why we took off his clothes. Then they told us we had to dress him.
Our response was an emphatic, "Nope!"
An enforcer for the Greek mafia (?!) loved me, and would come in to tell me jokes for a few hours about once a month.
He was HUGE.. biggest man I've ever seen. Well over 7' tall, and so ripped he'd have to turn sideways to enter the door. Needless to say people climbed all over him like he was a gym. A... little did they know he was an enforcer for the mafia, and B, little did they know he would occasionally go outside to smoke meth in his car.
He'd put down about eight burgers or cheese steaks in the course of a few hours, and about five liters of diet coke (he didn't drink, just smoked meth.. and profusely sweated).
Last time I saw him he went to the restroom and locked the door. About an hour later he finally came out. A smell of poo hit the bar. Turns out he went to the restroom to drop a deuce, and fell asleep.
He didn't make the toilet, instead he shat on the floor and then fell asleep in it. He sat at the bar a few more hours covered in his own poop. He was so big and well... frightening because of his job, we couldn't get him to leave.
He wanted to stay and tell me jokes.
Cousin was bounced from the bar, but the remaining cousin pulled me over the bar and said "he would own me" and that they could do whatever the fuck they wanted.
I told him not a chance, and that this was my bar and my rules.
So he launched a glass tumbler at my head (video evidence shows I somehow Matrix'd my body out of the way).
The bouncer and I got a hold of him, and we got him out the door. But not before his wife jumped on my back and started ripping out my hair.
They kept coming back to the bar that night (and yes, we had alerted and had police standing outside) demanding my arrest for assault and battery, and theft. They claimed I stole their wallets before we "jumped them." Kicker was, they left their CC and their ID at the bar.
It took everything in me not to order tens of thousands of dollars worth of dildos and send it to their apartment. Instead, I cut up the card and ID.
Four kids came to the bar, found a smoker outside, and proceeded to CHOP him up. No joke... an Oriental sword.
As I went outside with my friends to help the kid, they brought the blade down across his face. His face split open like a fish tail.
Many stitches were had that night.
5. Same bar... I had a drunk guy kick down the female bathroom door while it was occupied. He had a crew of about twelve, and they all said it was my fault cause he had to pee.
It was a holiday... I had no bouncer, no barback, no servers, no kitchen... just me.
6. Wasn't my customer, but my ex's.
Visiting her, I watched a guy leap on the bar, and proceed to grab a beer and start a beer enema. Yep.
I watched a guy get hit in the face with a skateboard there, lots of teeth lost there. I also witnessed a guy go outside to smoke a cig. As he did, he got jumped by another customer who suffered from multiple personality disorder. This guy was drunk and thought he was a werewolf, so he started to bite and take chunks out of the poor fellow's face.
As we got the 'werewolf' off, both guys ran off... one screaming hysterically and the other howling at the moon with blood dripping down his face.
That wasn't short at all... I'll stop now before I type for days.