Agreed, this has been one of the habits I've had to break during my computer engineering PhD at a scientific research lab. Initially I was just submitting the first solution I came up with without much additional thought.

My senior developer mentors ended up having to effectively rewrite all of it because while it was technically correct and efficient, it broke all sorts of other good practices (eg didn't fit the existing coding style), or added in additional library dependencies without much thought towards long term maintainability and backwards compatibility.

It was taking so much time for the handful of already busy developers to go through my work that I had to learn to slow down, properly study the existing code and think about writing high quality code that fits the existing codebase. They didn't have the time to put down all their other work just to spend hours walking me through improving.

As you mention, it was like with learning art, it's impractical for a teacher to walk you through everything, you have to learn to identify errors and things you need to improve through your own meticulous study, relying on the teacher to give you hints when you're stuck.