Yes, humour. For me I don't seek out the funny books. They're mostly just happy accidents. Or small funny snippets inside other more drama focused stories.
I usually spend my time in the romance, paranormal and fantasy sections of bookstores. Contemporary is something that I don't usually read, though I have made a few exceptions. John Green's books are one example. Those can't be called humourous books, but I've definitely come across some laugh out loud moments. Also, I do remember laughing at a few times at Anna and the French Kiss.
I've been told (by my mother, so its no big deal) that the humour I try to weave into my books works quite well. Here's a little fanfiction exert that she liked.
Tamina screeched with rage and kicked a mound of sand at him. She turned on her heels and stormed off into the darkness.You be the judge. It's not as funny as I remember it, but maybe thats because it was a long time ago.
"Where are you going?" he called after her as he brushed sand off himself with an irritated flick of his hand.
"To find a stick," she yelled back.
"What for? We've plenty of firewood to do the night!"
"So I can beat you with it!
I seem to find characters being 'sassy' very humourous. I just love Tyrions lines in the Game Of Thrones series. Peter Dinklage just delivers them perfectly. Also, after watching the Beautiful Creatures movie I really liked the back and forth between Lena and Ethan, but as I began to read the book I found that it was missing/wasn't as strong and was disappointed.
Do you seek out the humour, or is it a happy accident when you come across a story that weaves it in amongst other stuff?