Unreliable recruiters.
If someone insists on calling me at 8.45 in the morning to shoe horn me into a face to face interview that afternoon, they don't have the right to take the hump if I can't make it because of a doctors appointment. Even if I didn't, they're still calling me at 8.45 in the morning to get me to commit to an interview at 2pm. Fuck off.
Especially given the company they represent bailed on the telephone interview scheduled the day before.