Then there's those CO's with the good ole boy club and if you're not a part of it, good luck in other endeavors. Neither of those happened to me but I've seen it and heard it, many a time.
Ding, ding, Ding - we have a winner!
Back when there were 2 VP Rags and the east coast looked down upon the west coast, I checked into my DH tour in an east coast squadron with a west coast background. My welcome aboard interview with the XO & CO: "You know HAL Pilot, we've known the the other DHs since they were Ensigns. We have 8 of you but can only take care of 6. We just don't see you breaking out this tour." Since they tagged teamed me with this and since the COC was about a week before I checked in, I was stuck with this as the XO would be the CO when I had my last competitive fitrep there. I worked my ass off anyway, never could satisfy the JOs when they asked me why (they knew the situation - the Admin YNC who I knew as a YN3 heard the interview and told the Chiefs. The Chiefs told the JOs. The JOs saw my situation as the perfect reason they were not going to do 20.) and I got pack fitreps.
So I take an early retirement as a LCDR and it worked out great.... If I had broken out, I would have made CDR. I would not have retired before 9/11/2001 (my 20 would have been December 2001) and I would never have been hired at Hawaiian (they haven't hired since 2001 and probably won't until 2008).
To further put icing on the cake, I went to the annual VP Reunion in 2002 where this asshole skipper was getting ready to retire and was talking about moving to Hawaii and fly for either Hawaiian or Aloha. I said to him "you know I'm a Hawaiian pilot now. Hawaiian and Aloha are very selective. While I can't guarantee you a job at either I can sure prevent you from ever getting hired. I've known a lot of pilot a lot longer than you. I just don't see your resume breaking out......" He has been successfully blackballed at both airlines. I know that his resume was sent to both multiple times and it has always ended up in the trash.