I've burned out of my first job, where my work responsibilities steadily increased until I was simultaneously a software developer, a sysadmin for five racks of servers, a devops for one entire software platform, the help desk of ~50 users for the sysadmin/devops stuff and the go-to troubleshooter.

That happened because I just graduated and I was too effective at my job. Whenever management hit a problem they couldn't address, I became the backup guy they could always call in when all else failed. It became so bad that by the end my manager gave up trying to make me track all that I did because it would slow me down too much.

I've learned a lot during these four years. I'm back at that company but for a different project, it took hiring/dedicating multiple people to cover all of my previous responsibilities in a sustainable manner. I'm still a dual software developer/devops in a much smaller team, but I'm pacing myself by being only of them at a time per half-day.