I don't like pop-ups. They're too flashy for my tastes.
Once, my computer was super!infected with spyware/adaware/something like that, and a pop-up would popup every five minutes or something like that. If someone stayed logged in, they'd come back and see 30-something pop-ups on the screen. It's the most annoying thing to clean up, when the computer's super-infected. I swear, sometimes I wonder if my stepbrothers knew what sites they were visiting and what they were downloading >>;;