> Burnout is your brain giving up because it doesn’t think the benefit is worth the effort anymore. If you don’t have a purpose for what you are doing all your brain will do is obsess over the negatives. Every job in the world has massive negatives. You have to find a positive purpose for what you are doing to balance the negative.

This is spot on and was exactly my experience at my last job.

The one thing I'll add is that for me it wasn't about not having a purpose, it was about not feeling appreciated for all of the time/effort/energy I'd poured into that purpose.