A personal anecdote: I have recently discovered I was bored on a job because the tech lead, after working with a dozens of engineers who considered cleanup and simplification tasks boring and wanted to implement new features, stopped parcelling out those and kept them to himself, while distributing new functionality tasks (which I don't personally enjoy doing 40 hours a week) throughout the team.
A personal anecdote: I have recently discovered I was bored on a job because the tech lead, after working with a dozens of engineers who considered cleanup and simplification tasks boring and wanted to implement new features, stopped parcelling out those and kept them to himself, while distributing new functionality tasks (which I don't personally enjoy doing 40 hours a week) throughout the team.