It’s easy to mistake good for great, because greatness is rare—especially across multiple domains at once.
If you’re getting an average result, that will often be the best you can do. There will be only a handful of things at any given time that you can achieve a better than average result at.
Luckily, we don’t need to be great at everything. What’s important is striving to be good at the things that matter most, even if you can’t be great.
If it’s something that truly matters, do the best you can. If you do that, you’ll have done as well as you needed to.