It's always really weird that when I'm looking for a specific thread, I can never find it, but a few days after I give up it kind of resurfaces/makes itself visible to my eyes (because apparently it was there the whole time and I'm blind), and by then I've forgotten what I wanted to say. So I started bookmarking threads when I see them and want to comment on them but haven't got the words to immediately reply, but then I forget about those bookmarks because I hardly ever use that function 
