Comment by Hayarotle

You shouldn't, but it happens. The UI makes it much easier to open a new tab than to close older tabs (unless you close all of them at once). You even inadvertently open new tabs when you click on links and they open on a new tab rather than on the current tab. Unless you consciously choose browse in a way that avoids the proliferation of new tabs, you'll get flooded by them, as that's what the design leads to. Exceptions are browsers that don't save tabs between sessions, or that automatically close tabs after a specific number.