Great thread subject! I agree with Kat about screening well. That keeps creep rate for me about 5 to 10%. Most have my experiences have been great. Some average and a few horrible! Those I can't really talk about. My top 3 jerk behaviors:
1) threats of outing or telling others confidential things
2) being too rough or aggressive
3) hygeine! We all agree on that. Only had problems with that 3 or 4 times.