I love to laugh. Who doesn't? So when I pick up a book, it doesn't matter what the genre, I expect to get a laugh somewhere along the way. Even the saddest book or the most dramatic needs comic relief. (Yes, this is my opinion. Feel free to disagree because reading is subjective.)
So, when I write, I make sure I have comic relief. I just finished revising a sequel, and I took a considerable amount of time between drafting and revising. The result was a good laugh. Seriously, it was in a good way. I have a character who drops one-liners, and she had me laughing up a storm while revising. I forgot how funny she can be.
And even the narration had some funny moments. I wish I could remember what I was doing when I wrote those chapters because I don't think I'm very funny, and yet I created characters who are.
What's your opinion on humor in books? Should all books have some?