Humour's a great sell - if you can make people laugh, they'll like you, pay attention, remember what you said and possibly even pass it on. I can't remember the number of times I've used a Terry Pratchett quote to emphasise something, even to people I know have never read him (which is usually a mistake, because nothing kills a joke faster than having to explain it.). Even when I teach - software engineering and programming, perhaps some of the driest subjects around - my students remember what we go through because I act like a nutbar, waving my arms around, throwing my stationary across the room and anthropomorphising an operating system.

It's not for the faint of heart, however.
My partner is currently developing a video game. It's all wrapped up in secrecy at the moment, so I can't give details except to say that there is, at least in theory, a story to it, and said story is being handled by yours truly. He loves comedy, however, and spent quite some time adamant that this game we're developing should be comedic.

I took pains to talk him out of that. Not because I think it wouldn't work - there's no reason the game couldn't work with a comedic tone - but because using comedy rather than straight narrative is about a hundred times the risk. You risk alienating people who don't like your humour, you risk making your whole premise, and by extension your work, look "silly", amateurish, and not worth people's time (or money). You risk looking like the kid at the party telling his dad's jokes and insisting people should be laughing. Because comedy - or perhaps I should say comedy that is actually funny to a good proportion of people - is really hard to do. But it's really easy to do poorly.

You know the feeling of watching someone who thinks they're being funny when they're really not. I've found it happens most often at weddings, during speeches. Some people can make them genuinely funny. They pick up on aspects of the bride or groom or situation, and turn it into a joke. And it doesn't take much - a tone, inflection, a well-timed pause on a word. But there's always the one person who tries to be funny. You can feel it. They use general jokes and setups instead of something that relates to the people, they don't listen to what's gone before, or the tone of the room, to match their humour to what people have been laughing at, or give what jokes they do have time to breathe.

As soon as someone knows you're trying, it isn't funny anymore.

Does that mean don't try? Of course not. It just means you need to understand the risk of humour, so you know how to support a book if someone isn't laughing. More importantly, it means humour can't stand alone. There has to be story as well. Even Seinfeld and the Simpsons had a story behind each episode - not much of one, granted, but then, it's only a half hour show. Humour without substance behind it falls flat - there's nothing to counterpoint it, support it, echo it. It really doesn't play as a back up plan if your story isn't working.

It's not enough to just be funny. You have to have all the things a straight narrative has - compelling characters, interesting arcs, a well structured, well-paced plot without too many holes, development, emotional connection - and then add humour on top of that. And that base had better be solid, because comedy's going to show up every problem.  Comedy isn't wallpaper to cover the cracks - more like spray paint to highlight them. Use with caution.