One thing I learned about HN that I don't even think about anymore is that upvotes are only weakly correlated with the quality of the submission itself - they usually reflect the interest in the topic revealed by the headline, or signify there's good HN commentary, or both.

IIRC, back before the "favorite" feature was introduced, people would use - and some still use - upvotes to bookmark interesting threads.

Second thing I learned is to always at least skim the comments before opening the submission itself, to gauge whether the latter is even worth it. Quite often it isn't. Here I thought it is, but the text was so long and... off somehow, that I got back to comment thread and read it more carefully, and now I know why it's off and that it's not worth it (for me personally) to read it more carefully.