Not because of any extraordinary talents did he succeed, but because he had a capacity on a level for business and not above it.

Fit does more work than brilliance in most jobs. Someone whose abilities sit at the level the work requires gives it their whole attention and misses little, while a mind far above the task spends half its time elsewhere and makes careless errors. Being well matched is not a lesser thing than being gifted.

Have a look at whether your current work is too small for you or too large, since both go badly. If it is too small, the boredom will show up as mistakes rather than as complaint. If it is too large, get the specific missing piece rather than working longer hours.