[filchermcurr]

As a fellow multi-thousand tabber, I can explain what happens with me. So you're browsing, say, Reddit (maybe last month). You see something interesting. Two tabs: One for the content, one for the comments. You read the content and come across something you want to comment about or see if others are talking about. So you switch to the comments. Oh, somebody linked to something else. Another tab. And then you go down that rabbit hole and back to your original Reddit tab. Repeat.

Then you start to work on a project. You have various relevant links open for that, which of course results in opening even more tabs that branch off from those. But then you get distracted and there's another group of Reddit or HN tabs. Oops, right, I was working on that project. A few more project tabs. Then a bunch of Reddit / HN tabs. Then you start a new side project. Etc.

Why not close those comment tabs? Because you're interested and want to see all the new comments! Or you got halfway through and walked away and opened a new tab when you got back. Or you think 'that'll sure come in handy when it's time to work on <some project>, I'll come back to this later for sure!'.

Now, rather than doing the sensible thing and going through all of the previously opened tabs when you're bored, you open a new Reddit / HN window.

(Possibly an attention disorder.)