Well, apart from myself, I know who shafted my career at particular points. One, which I think is the classic, is the 'new' sqn cdr when you have been on the sqn for two years.
I had been doing the sqn adjt job for two years (rather than the 6 months secondary duty). I was approaching tourex and suggested to the new CO, whom I had thought was human) that I might step down and allow someone else to carry on and I would be available if need be. I was accused of gross disloyalty.
Please to note that that CO was 1021'd in his next appointment.