Not in this scribbler's opinion. Of course, there are books whose intention is just to be funny. Some of them even suceed. But really good books are not one-note, just-funny (or chase-escape-here's-your-happy-ending, or whatever). A good book is like... Like being in love. It makes you happy, sure, but it's also thrilling, exhilerating, maddening, moving, terrifying, bittersweet, uncomfortable. It makes you vulnerable. But in the end, no matter the outcome, there's almost always a reward to be had. Whether one can grasp said reward is a different matter.
I will leave with a quote by Franz Kafka, which, though perhaps a little extreme, suits my purposes well enough in closing:
I think we should only read books which bite and sting. If the book that we read doesn't wake us like a blow to the skill, why do we read the book? To make us happy...? My God, we could be happy even if we had no books, and if really necessary we could write books to make us happy ourselves. But we need the books that affect us like a disaster that hurts us greatly, like the death of someone we love more dearly than ourselves, as if we were driven out into forests, far away from any human beings, like a suicide, a book must be the axe for the frozen sea within. That is what I believe.