Yes, I'm well aware of R's many faults, I have my own long list of R caveats I hand to new hires, but not bothering to learn the damn language is no reason to complain about it. First, RTFM.
1) There are just quirks in implementation that are nonintuitive. I constantly find myself doing things I would do in other languages, to do simple tasks, which fail for no good reason, albeit an obvious one once I find the right documentation.
2) The manual you describe is flat out unhelpful in many cases. The suggestions that constantly come about "check stack / google" are suggestive of just how poor that documentation is