While the rules can certainly be complicated, I think there are really a few simple guidelines to follow to avoid trouble...most of the time.
1). No blatant plagiarism
2.) If you post to a community, make sure you understand the rules of the community and make on topic posts.
3.) Don't tag your posts inappropriately (e.g. don't tag it #crypto if it s about the weather)
4.) Upvote posts you like
5.) Be careful with downvotes
6.) Posts deemed to be political or otherwise controversial can lead to trouble. Not saying they should not be made, just that they can lead to seeing a lot of 'unfriendliness' but that's true anywhere on the net and isn't particularly unique to hive.
There are probably some people and communities that don't show quite enough patience with honest mistakes from newbies but in general it is not a big deal. Don't let a few bad experiences here dissuade you. You will probably have more. However, in the long run, you should have far more good ones.
Thank you. Those are some excellent points!