I had a hunting partner who used the phrase "eat sh.t and die" when unhappy with someone. He was a doctor so I decided he needed to spruce it up a bit. So I had a plaque engraved for his office which in Latin said eat sh.t and die. Stayed on his office wall for almost 40 years, right next to his diploma. He said nobody ever figured out what it said.

My favorite Latin insult is the following one.

Mater tua tam obesa est ut cum Romae est urbs habet octo colles!
Your mama is so fat when she goes to Rome it has 8 hills!