I've contributed a lot of code and have had vastly different experiences. Sometimes people are excited and accept a PR without question. Some people just ignore PRs. Some people make you feel as though you've just spit in their face. I had one pull request that I thought was reasonable which was met with a ridicule from the maintainer at how useless my idea was (to him). I'm a seasoned programmer with my own projects and a lot of code under my belt but, even knowing how these things work, that one really soured me on his project. I can't imagine if a novice who was excited at their first PR was treated so poorly.
If I could suggest anything to maintainers, it would be to simply appreciate that somebody was trying to contribute. If their code doesn't meet your goals or standards, try to still respect that they spent some time on your project.