This one has photographic evidence

Two young Latino guys come in at 4am. They are expensively dressed with Rolex watches, and obviously years of English classes but no experience actually speaking it. I'm guessing they are privileged rich boys in their country; they have that attitude where they are used to being waited on and never give a thought to how they treat other people. I'll notice this a lot in different cultures. Americans tend to treat service staff with much more respect than most foreigners. I think we look at it differently, many people worked their way through college or have waited on people at some time, while in other countries you would never take a service job if you were in the upper class. Here your server might just be finishing up their masters degree.

These guys have an annoying habit. Anytime they need something they pound on the bar and say "hey hey hey" until I respond. It doesn't matter if I'm in a conversation with someone or making a drink. He also insists on paying as soon as he orders. They order the two most expensive steaks on the menu. The less drunk one gets a beer. The check is around $100, he looks at the tip portion on the credit card slip for a few seconds then crosses it out as soon as he realizes what it means. The more drunk guy falls asleep while waiting for the food to come, I don't bother waking him because I know they'll just ask why the food is taking so long. It's not, but I can tell when people stare at me every time I'm in view that that's what I'll be asked if I'm dumb enough to make eye contact.

The steaks come out and these guys are hunched over their plates, shoveling food in as fast as it will go. One guy gets a piece of fat from the rib eye he's eating and just hocks it out onto his plate. No discretion, doesn't even try to be quiet, just spits it out. A few minutes later his brother does the same thing, but he loudly spits his food onto my bar, almost going over and into my ice. He sees me staring at him and quickly puts his head down and continues eating. I guess deep down he knows what good behavior is, he's just grown up in a situation where he does whatever he wants.

They are slowing down. Their heads get closer and closer to the plate. They each still have their fork in hand. Drunk guy passes out first, puts his hand into the food and rests his head on it. His brother is asleep with his head hanging but in an upright position. I should probably wake them and tell them that's not allowed, but I want nothing to do with them.

I come back a few minutes later. More sober guy is still there with his fork in his hand. More drunk guy has moved his hand and has his face almost nose first into his plate. I leave.

I walk around the bar again and there is another patron taking her picture with the guys. Cute blond girl is trying to put her arms around them while making hand signs for the camera. The hostess is begging me to let her call security, she gets abused so much she loves to be able to give a little back.

Security comes and shakes them both awake. As drunk guy sits up, a piece of potato and a chunk of steak sticks to his face then falls in his lap. His hand is covered in ketchup, which he then wipes all over his shirt. If they had a room in the hotel security would just escort them to bed, if they weren't staying here they were escorted off the property.
TL;DR