Which Grad Student Are YOU?

While I was talking to my brother tonight at dinner, I came up with the following.

Many grad students I've met are in grad school because:

1) They either realize what you're doing isn't what they want to do; or
2) They realize they don't have enough credentials as they went along; or
3) They are liberal arts graduates; or
4) They just love school that much.
[And please, all ye grad students/graduates, add your own criteria/reasons. I'm interested in hearing what you think.]

Looks like I'm 2, 3 and a bit of 4. :-D