Only three in twenty odd years.
1: Brand new FO, TRE was a dour, very religious misery who would have been right at home burning heretics. Made me repeat the EFATO about twenty times for no good reason except that he may have suspected some deviation from the word of god. After the 10th or 15th repeat, with the LHS looking utterly horrified and me sweating buckets, the law of diminishing returns stared to set in and he threatened to ring head office and have me taken off the roster and given the airline at that time, probably dismissed. I survived but went shaken and pale to my base manager who informed me that the problem with Capt. Torqemanda was that "he's never had a blowjob".
Collapse of stout party.
2. Years later, TRE took an instant dislike to me as I have never served her majesties armed forces, unlike him and the LHS who were as thick as thieves. Got through day 1 (checking), license signed, then day 2 (LOFT) arrives. At the end of the exercise and in the briefing room, He ripped my paperwork in two and announced that he would never let his mum and dad fly in any aircraft that I was in. No further explanation given, do not pass go, do not collect 200 quid, sod off. Repeated the whole thing a few days later with different TRE who was at an utter loss as to why I was even there. That was a great educational experience.
3 Fast forward a few more years. Utter stitch up of a "command assessment" as it became obvious that I was never going to make it due to ticking all the wrong boxes - age, previous types and airlines, inside leg measurement, lack of military service, parentage and probable spiritual destination. Screaming bollocking during "debrief" after which I was asked if I had any questions. I asked if they could tell me where I had gone wrong to be informed that "no feedback is given" Looking at the blood running down the walls I started to wonder what the last 20 minutes had been about and if I was going to wake up soon and realise I shouldn't have had the fish last night. Nope, I was stuck with it.
I left their employ shortly afterwards.
Since then, nothing, such people seem to be being weeded out (the second airline had a major cull after the CAA sat in on a few training sessions). Now in the LHS and treated like a grownup it all seems like the dim distant past. Reasonable chance of being in the training seat myself at some point and I would NEVER do that, even to my worst enemy.