Death marches
Sometimes a project has a mountain of bugs to fix, and it takes months to work through them. I’ve heard this described as a “death march” (an unfortunate use of the term), because it’s generally unpleasant work often accompanied by overtime, stress, and pressure.
There are lots of reasons why this happens and lots of advice about how to avoid it. I don’t have a magic solution here. I also don’t accept it as an inevitable part of developing software, and neither should you.
Fixing bugs can be fun, but not when under extreme time pressure and lack of rest. You can’t even do it well in those conditions!