<|im_start|>system
You are a helpful AI assistant.<|im_end|>
<|im_start|>user
Why do most YouTube video thumbnails feature a face with some exaggerated expression?<|im_end|>
<|im_start|>assistant
Most YouTube video thumbnails have exaggerated facial expressions as they often lead to more clicks, due to them being able to draw a user's attention easier. They can trigger human brains to be more aware, and focus on them, which is why they are so prevalent. They're also often used in combination with bright colors, and sometimes large text, which has a similar effect.<|im_end|>
<|im_start|>user
Are there other strange things happening with thumbnails I don't know about?<|im_end|>
<|im_start|>assistant
Sure.  Many thumbnails are made with clipart which actually has nothing to do with the video.  They also contain headlines that say shocking things were just discovered - when in reality either those things are completely false, or things that sort of resemble them were discovered years ago.  Lots of them claim to reveal secrets (or at least things somebody doesn't want you to know) when those things either aren't secret, or aren't true, or the person really doesn't care whether you know. Lots of video thumbnails (and headlines) take an emotion keyword like destroy, hate, disgust, humiliate, love, etc, and render it in all-caps with exclamation points, just because that causes slightly more people to click on it than it causes to avoid it.<|im_end|>