Oddbean new post about login | logout There is probably someone you follow that has posted something while you were sleeping that you didn't see because other people you follow have posted dozens of times each after that and you missed that single post.
ohhh. That's a UX fix then. I think Instagram used to have that, and I actually appreciated (maybe twitter too? I forgot). Basically: You keep scrolling in your feed until you reach a point where there'd be a UI line telling you "You've already seen posts past this point", and when I've seen that, I'd usually stop and go back to the top.