If you really need to ask people why they left then you have got your rose coloured specs on. The reasons for leaving are too numerous to list and are really quite obvious if you scroll through this thread again. If you like I'll shortlist a few.
****** Trainers
****** management
****** Captains
Crap staff travel
Crap medical
Crap leave system
Crap request system
Crap rosters
Crap hotels
Polluted air
Poisonous working environment
endless BS to get in the LHS
four different pay scales
rife nepotism
poor treatment of S/O's
having to deal with those mutants in Crew Control
(out of breath, but that will be good for a start)
Let me guess you're an A scaler right? And only spent 3 years in the right seat before you had a few sectors of beers with one of your ex-airforce buddies and then just tootled on your way to "commander"

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Times have changed mate.....Let me tell you it ain't no party any more!