Aside from Cliff Racer swarms, what is the worst thing that's ever happened to you?

For instance, because I use MCA and Starfire's NPC additions, I got attacked by 9 npcs in Caldera at a very low level. Not all at once, but one group of 3, 2 groups of 2, and two more individual npcs. I had no potions and I think it was just terrible luck for me.