Knowing that I'll have to relive and relearn the damn primary school-to-high school experience of lessons...
Edit:
Actually, no, now that I think of it, it's more the thought of resetting the progress of previous life and knowledge that is pain and knowing that I had a past life that I was already settled in...
Also, do you sometimes dread looking into your inbox? Sometimes I do...
Statistically, most animals are nematodes