but it looks like that there's no system in meriting. You never know for sure what others will like. It seems to me that you just need to take it easier: it's nice when you are noticed, but if no one notices... well, that's okay too! 
There are personal whims but majority of the time quality posts is universal and can be identified by anyone. The fact that a post isn't merited does not mean other users did not find it to be a quality one, but it could be they did not have smerits at the time of reading it.Just do you and put some effort into your discussions and you will get merits eventually.
Yes, the key word here is eventually. You never know when it is going to happen. Just because quality posts can be identified by anyone doesn't mean they will be rated. Very often, qualified posts get lost in the flow of discussion and got forgotten. And if ordinary users may not have sMerits, then the merit sources have them. But how to understand that the merit sources are looking at topics in which a particular user writes? I don't know exactly how they choose who they reward, but the likelihood that they will notice your post decreases with each passing day. Therefore, it is impossible to talk about the system in meriting, in my opinion. I will agree here with Who is John Galt?