They're often cheesy and occasionally very stupid.
They are reused so often you get sick of it.
If we extend advertisements into the world of pop-ups, now we're talking about malware, and other harmful stuff.
Pop-ups can be outright filthy, advertising "sex chats" and the like.
If advertisement didnt have the very occasional benefit of actually showing off a nice, desirable product, there would be no redeeming factors for ads at all!
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Currently playing: Luigi's Mansion 3 and Mortal Kombat XL SMM2 Maker ID: JCvgluvr 21J-H86-FNG. I specialize in action stages and SMW design.