Thumbnails are the worst. Most of us hate them. Clickbaity, unrealistic and the most important: most of the time it doesn't even appear in the video. It hides the true colours of the video. It reduces its cogency. But from the creators' POV, it is a great tool to create suspense, attract an audience and preach something. Maybe sometimes the elements we hate are the reason why we love the whole thing. It's all about the sub-conscious :)

PS: It's not my thumb :D