I know it's said a lot by many many people in fandom, but it always bears repeating: leave comments on AO3 fics.
- even if you've left a comment on every other chapter (it's not weird or obsessive, the author probably developed a crush on you by the 5th or so comment);
- even if the fic has been finished and published for years (fanfic exists in a dimension where time doesn't exist; yesterday, six months ago, ten years ago - it's all the same);
- even if the fic is unfinished and the last update hasn't been posted in years (the author still cares, whether they plan to finish or not - it's still nice to know that there's still someone out there who enjoyed / is enjoying it);
- even if all you say is "Kudos!" or a heart symbol or something seemingly "insignificant" (it's not insignificant; just the fact that you took the time to open the comment box makes the author happy);
- even if you've left a comment / comments before and you're back for whatever reason to re-read (what? you've read it already and you want to read it AGAIN? and you're leaving a comment to say so? the author has passed away from delight);
I just think that if you're in fandom spaces, it's so so important to let people know you enjoyed a thing they made. It makes people feel good, feel valued, and feel motivated to make more things. It strengthens communities and builds positivity. And it's the only way to defeat the robots - nevermind, that's another post.
So yeah. This post is for whoever needs to hear it.