What I found (I wrote a pretty large open source project and receive hundreds of emails every day about it) is that most people are only willing to contribute to open source to the extent that it scratches their itch. They feel that their obligation ends as soon as the code is written, and the maintenance of their code falls on you.

So from a maintainer perspective, you have to act like people's contributions are your contributions. You have to evaluate the code as if you have to maintain it later, you have to understand the circumstances surrounding it, etc. You have to be aware of everyone's concerns at the same time and make sure you don't end up messing up other people's use cases without good reason. And more often than not PRs reflect a "selfishness" of sorts wherein it solves their problem but breaks the general case.

In four separate occasions, people tried to take control of my github organization and npm repos by complaining to github and npm support, because they disagreed with the trajectory of the project. Some people seem to have no respect for OSS.