Not being constantly late on her shift.. especially when I travel and sort out 3 kids before hand and get there in plenty of time, and she is childless and lives round the corner. Grated me that did, especially when the rest of the staff are so used to it, they just accept it... sorry, but that is never acceptable, I felt so sorry for the midwife doing the shift before having to hang around to do the handover. Also trying to 'test' me in front of women on things she had never covered with me before. I was asked on my first ever shift to interpret a ctg, I wasn't asked how much I knew first, never mind the fact I'd never seen one before.
Good mentors ask where you are up to, help you relax and chat to you like you are a person instead of something scraped off their shoe. Oh, and they make an effort to help you with your paper work by signing it when they say they will instead of hanging onto it for a week after placement has ended and still not even looked at it (can you tell my mentor didn't impress me ..lol.)