Establish a quality-centric mindset
Having high quality standards for your project is a matter of practicality, not pride. To understand why, it helps to remember that "bad code" is typically hard to understand, hard to test, hard to change, and hard to reuse. Regardless of how useful your project is to the world right now, these problems will get in the way of its future progress.
Any one of these negative traits of bad code can make a maintainer's job painful, but when you combine all four of them it is like wearing a pair of lead boots while trying to run a marathon. Even if you are capable of supporting your project in its current state, these hindrances will gradually chip away at your ability to be responsive to the needs of your users while simultaneously eating up time and energy that you could be using to improve your project's strengths rather than fighting against its weaknesses. Once you head down this road, your project stops being fun to work on, and starts feeling more like a burden.