Cryptic tip
Being a waiter is a tough job, and I’m fully of the opinion that everyone who plans to eat in a restaurant in their lifetime should have to go through one afternoon of waiting tables in a café. That way they’d understand a little of what it’s like from the other side, and maybe have some sympathy. It might stop instances like this one.
This is purely about humiliating a real-life human being for laughs. Sure, you’ve left a tip, but the server will have to clear up this ketchup mess in order to get it. Whoever did this seems to think of servers as several rungs lower than him on the ladder, which is an appalling way of treating people, if you ask me.