What else do you enjoy? Do you derive satisfaction from solving problems for users? Maybe you're trying to perfect something that's less interesting to you than another problem on your plate.

If positive user feedback 'gets you off,' as it were, try releasing something that isn't as perfect as you'd like it to be and see if there's any measurable difference in sentiment. I bet there won't be. Do it a couple more times and hopefully it'll break the pattern.

For the other case, try time boxing yourself so you can get back to the more interesting challenge. Make that other thing 'perfect' if you won't.