In most fantasy settings, the apex predator is the dragon: powerful and cunning, with many physical attacks and a fearsome breath weapon. In all of the 26 years that I play RPGs, none of my characters has ever gone up against a dragon. They're simply too powerful and too rare to make a good adversary in almost all campaigns.
[Spoilers for the Jade Regent adventure path]But in this scenario there was an ice dragon that had been attacking a village near its lair. We found out this was because someone had smashed her eggs and left an amulet linking the attack to the village. We also found the perpetrator and killed him (or rather, we found his hide-out, were attacked, retaliated and then found out what had happened with the eggs). We tried to reason with the dragon, but it would not listen: it had vowed to kill all the 'warm-blooded apes' in the village. The attack was repelled (as had happened before), but at the cost of several lives.
The next day, we made the trek to the dragon's lair, to surprise it before it could heal up completely. We damaged it quite badly, and it was my character, the Cavalier Logren, who dealt the finishing blow and decapitated the dragon.
OK, so it was a dragon who had been damaged before, and who was not at her best, and who even managed to fumble her first attack. But still: we slayed a dragon! I'm looking if we can mount its head on one of the wagons of our caravan -- if that's not a good deterrent against bandit attacks, I don't know what is.