There are two other aspects that really attracted me to ultras (other than impressing my co-workers), the distance and the scenery.
That's why people react like ultrarunners are 'crazy', because ultramarathons are so far out of what society considers 'normal'.
Of course, the other amazing aspect of ultrarunning is the scenery. Every race website I've seen is full of photos and videos of amazing athletes performing amazing feats in the world's most amazing vistas. Want to travel to cool places and see cool things? Take up ultrarunning.
After all, in a 100 mile run there has to be something cool to look at.