[Practicality]

Targeted ads. They look like interesting articles but then when you get there it's just a few facts and then more ads. You end up making somebody money from ad clicks but never find out the information.

Ironically, the solution is to usually just google the topic, satiate your curiosity and move on. But I can get stuck in a looking at ads for an hour before I realize what is happening. It's such a waste.