That's probably the main reason I left what was otherwise my best job. I knew that if I stayed longer, I'd never be employable anywhere else, both because I'd have stopped learning, and because I'd have grown too comfortable/scared to move.
The other problem with an easy job is the boredom. If you are in office or even remote but present, remaining engaged but bored for 8hrs/day is torture.
That's probably the main reason I left what was otherwise my best job. I knew that if I stayed longer, I'd never be employable anywhere else, both because I'd have stopped learning, and because I'd have grown too comfortable/scared to move.