Practice the Hard Stuff
You get better at something by practicing the things you are bad at, not the things you are good at.
So often piano practice turns into a concert for oneself. Just playing the things you are comfortable with and getting the feeling you are making progress while not actually getting better.
There is this study with a baseball team learning to bat. They split the team in half for practices. One group the batters were pitched random pitches. Curve balls, fast balls, …
The other half were consistently thrown one type of pitch for a session.
Which group got better? Which group felt like they got better?
The random pitch group didn't hit as many balls in practice and they felt like they weren't making progress. But in the games their hitting improved.
The same pitch group felt like they were getting better because they could hit a lot more balls in practice. But in reality this group didn't get any better in a real game.
Several lessons here.
Make practice match the end goal (i.e. perform better at a game).
Real progress can feel really slow and at times frustrating.
Are practice session a vanity project or are they serving their purpose to acquire skill?