No they don't. Feelings are inherently subjective and i'm talking about the material realm. Even if as a materialist, you can't deny that feelings don't map well with objective reality, that they are material in nature is irrelevant to the quality of this mapping.

So feelings exist in some spiritual heavenly realm as opposed to the real physical realm we all share?

I don't really believe that. I think stuff like someone being happy is objective to everyone and everyone share the same physical realm with that person, even if they can't really be sure if that person is happy or just faking it. So, the perception of the happiness can be subjective, but its existence in itself, not really.

People might be happy or not, that's an operationnal hazard for human beings that we try to mitigate in the best of ways. But if you start to do things solely to make people happy without taking rationality into account you just end up with pure ideology after a while. And that eventually collapses because people can no longer relate their goals to anything actually useful to them.

You can do a lot of small things solely because you want to make someone happy and it's not compromising a project.

Like, every now and then, you can, instead of telling a fresh contributor "your code sucks, go fuck yourself", try to point them out what sucks in the code, quickly fix it up and then add it in to the project. If you don't have the time and energy for that, which is quite understandable, you don't need to, and you can just tell them nicely that "sorry, but the expectations we have for the security and extendability of code in this project is not really met. But we'd happily take in your contribution if you can find something a bit simpler to start with!" or whatever.

Point is, we only contribute to open source projects because we feel we get something out of it. It's different things for different people. For some, it's because they feel happy about thinking they've contributed something that might make otehrs happy, for others, it's the credit and fame, for other's it's wanting to improve their skillset. No one (or.. almost no one) becomes a part of a community, or uses a project, solely due to technical reasons, like "they really use composition coherently" or "dayum, those static guarantees - so good."