I always sit the new person down and explain what an FTO is. I usually tell them I am not there to be their friend or drinking buddy. They usually try to by lunch or something which I always refuse. I never take advantage of being a trainer. It is easier to be more friendly later in the program then to be too friendly up front. I tell them I will treat them like an adult but I expect them to be responsible for what they do (no bullshit excuses). I tell them that I will fail them if they are not up to being an officer, but if they do fail it is because I did not teach them well enough.
I also let them do all the driving unless they start testing me as to my status as a training officer. Nothing says I'm the boss like sitting in the passanger seat for a shift and getting dinged on the DOR. Only had this one time and it was a great indicator that the guy did not understand a paramilitary rank structure. I'v never failed anyone, but I did have one quit when I told him I was recommending an additional two weeks before letting him out on his own. Lately I have also started telling the new guys that if they are there to be a lazy slug, or a JBT that they will not make it past me. So far everyone I have trained is average or above average.
Strange crap from other FTOs;
Having new guy carry FTO's bag to and from the car.
Having new guy do all the paperwork asking other officers questions while FTO was watching TV.
Having new guy buy beer for the regular drunk LEOs at local bar.
Calling new guy names like rookie, new guy, and pointing out failures in roll call.
Telling new guy to buy lunch for the shift or FTO.
Treating them like slaves, or hazing them.
Oh, and buckle up good because it's scary as hell in the passanger seat sometimes.
Edit: Great advice in the above posts.