Dragons have had a terrible reputation problem for centuries, and honestly, it might all come down to one thing. Think about it. You're sitting on a mountain of gold, you've got wings that could take you anywhere, and yet somehow, nobody ever thought to bring you a decent cup of coffee. Not one knight, not one villager, not one brave soul showing up with a warm brew instead of a sword. No wonder they're cranky.
Centuries of treasure guarding with zero caffeine. That's not a monster, that's a hostage situation.
The thing about dragons is they actually had a pretty good setup going. Enormous cave, no landlord, all the gold they could ever want, and a built-in heating system. But without coffee, none of that matters. You could hand someone the keys to a castle and if there's no decent brew waiting inside, watch how fast the fire-breathing starts.