I just visited a discussion forum, and saw a thread that was 15 pages long, but I only looked at the last posting to it and noticed that it was more than a whole screen of text. Since I hadn't read any of the prior posts, I had no idea what the context was, but why should I spend my valuable time reading?
I also didn't pay any attention to simple clues about the discussion. Since I didn't skim any of the previous posts, I didn't noticed that there had been a lot of dialogue in the days leading up to that final posting, and that several days had passed since the final post, suggesting either that the final post had put to rest much of the argument, or that it was so stupid as to make everyone else give up and abandon the thread. If this had occurred to me, I might have resolved the question by noticing that the final post had a respectable number of up-votes from readers, suggesting that this one final post had probably been a satisfactory wrap up to the thread to that point.
I just didn't want to read so much text. It would take too much of my time. It never crossed my mind that it must have taken the author at least as much time to write as it takes me to read. I just thought it was inconsiderate of the author to put a big pile of text on the screen and not just tell me in a simple sentence or two what it meant. Of course, since I hadn't read the entire thread, I had no way of knowing that the author and others had done just that, many times, in the previous posts, and that the short versions had been unsuccessful in persuading the other participants to the debate. I didn't realize that the big long post I saw was an attempt to explain in minute detail exactly why those shorter versions were to be accepted.
It's possible that, had I read the entire thread, I would have understood these things. But that would have involved taking the time to read and think, and I've got better things to do. So I'll just helpfully post as a comment, "TL;DR". Everyone needs to know that I can't be bothered to read.