Halflings get racially profiled because everyone knows they're allthieves"expert treasure hunters""rogues".
Most shops have a "No shoes, no service" sign posted. Because see above.
If a halfling wears shoes, they can't make Stealth checks.
Kobolds are not in any way related to dragons.
Eating kobolds (it's surprising how many of the PCs this actually comes up with) will give you cobalt poisoning.
The goblin life cycle can be measured in rounds. That's why there are still goblins.
No one is really sure whether gnolls actually have a language, or if it's all just meaningless insane cackling.
Dwarves are Norse, dammit, not Scottish.
All hill giants have names that end in "-Bob", "-Jo(e)", or "-Sue".