Let's not forget:
SLUF = Stupid Little Ugly F***er
ROLF= Right Obnoxious Little F***er
IFBAS = I'm F***ing Boring As Sh*t
OSLO = OuterSpace Liaison Officer
We also had an exchange pilot who had been given his life-long callsign by the USAF. However, we thought he looked more like Shrek. He objected and it stuck. He objected more strongly and it stuck more. He was a very big bloke....he threatened to kill people and return to the US and thereafter we called him Shrek behind his back.