Reasons why I experienced burnout many times is for example being denied growth opportunities even though I fullfil all the expectations set by my manager.
Being assigned on tasks which are extremely simple and not challenging.
Having to deal with things which has nothing to do with product / software development, example long discussions about how to change git branch name.
Incompetent leadership, and incompetent employees who are blindly following, creating terrible software development practices harming the business but somehow making stakeholders happy, until, well layoffs...
By far the biggest reason I burned out is because , I care about my work, I care about the customers, I care about the people and I absolutely put business success at the top of my priorities but somehow non of those qualities are being valued, appreciated and never reworded.
I had terrible micro management, a tone of responsibilities at certain companies and a lot of work. Never have I ever experienced burnout due to "too much work".
Sleepless nights, cold sweats, back pain and more serious symptoms which I'm not comfortable sharing ALL stopped when I reduced how much I care.
I feel like they won.