I'm more of the 75,000 tabs faction, which is probably why I use 3 monitors. I prefer to have all the windows I'm actively working in open in parallel. With one monitor, the handling is too fiddly for me and the windows are much too small. If only one thing is in the foreground, I sometimes lose the context or the constant jumping back and forth annoys me.

Edit: Just looked it up, there were like 30 tabs ;) But also more browsers, because it gets too much in only one.