Tom Christie has some very good things to say on how to successfully maintain an open source project without losing sanity.
Truth one: There are, and will always be, a non-finite number of possible valid issues to address. Your code can always be better polished, your APIs better defined, and your project more fully featured. Your documentation can always be better. The ecosystem within which your project lives is constantly evolving. You will never run out of things you could work on. Ever.
Truth two: You have finite resources. Damn.
If you are an open source maintainer, contributor or even a user do yourself a favour and read what Tom has to say on the subject. Tom is the creator and maintainer of the Django REST Framework, a hugely successful open source project so he really knows what he’s talking about. And for what is worth, his conclusions mirror mines.
On a completely unrelated note, I met Tom at EuroPython 2014. He was so nice to come and meet me minutes after I was done delivering my REST API for Humans talk. Good vibes.