Generally devs who are too arrogant to accept help or constructive criticism. There’s this data visualisation library that missed a specific feature that psychologists use quite frequently, so I added it myself and opened a PR. The maintainer closed it because people should use whatever he’d already implemented. It’s like not giving someone the option to listen to disco because rock music is better. Yeah, cool story bro. Now all my visualisation projects depend on my fork instead. Same with the now abandoned Material Design Library devs. They didn’t have a drop down with free input, so I opened a PR with my solution. Closed as it was out of scope, simply because Google didn’t specifically include that in the Material specs, only an input and a drop down separately which my solution matched. I also opened a PR for an obviously missing feature (being able to validate forms via JS), closed as this behaviour wasn’t in the Material specs either. No wonder MDL died before it was ever finished.