My colleagues loved me, I got great performance reviews, but I didn't feel like I was learning or growing. I was severely burnt out after working on a couple projects that exploded due to organizational problems. I went through 3 managers in a year because of reorgs and departures. Ultimately I left that job because I tortured myself - what was I doing, what value did I add? How would I get a job after this when my skills were out of date?
Meanwhile the company's stock has tripled since I left. Even if I had sold every time my stock vested I would be a millionaire by now. I grew up poor, and the security of having that money in the bank would be life-changing. Instead I'm at a new startup where I'm not any happier, but I also don't get a million dollars.