Here's something serious.
I think the world would be a better place if there were more fart noises and nudity. In every situation where something sucks, there should be a fart piped in. Congress, fields of battle, at the symphony: farts.
Here's something else that's quite serious. Diarrhea. That is all.
Short Answer: I don't think 'serious' is a topic unto itself. Taking into account that my number one goal is to be entertaining, I'm sure you can understand why I head for humour first. With serious topics, it's not so easy to be sure you're entertaining people. Like, an essay about my dead aunt might not do it for you. But a picture of her tits? That'd be gold.