I also understand life can't be all laughs. Reality sometimes sucks, frankly. But to me, the best stories strike a balance. Even the most dramatic tale, if it desires to be true to life, must have some lighter moments, right? There are arguments for and against this.
One story that comes to mind on the against side is The Road by Cormac McCarthy. I wasn't able to read to the end. It was too emotional for me. But I read the summary to know how the story ended and can imagine there really weren't any light moments in that tale, yet it was excellently written, powerful. So, there are exceptions.
On the for side is The Glass Castle, a memoir by Jeannette Walls that I thought was beautifully written. Ms. Walls grew up with quite eccentric parents in some of the most dysfunctional circumstances one could imagine, and yet there are humorous moments where it shows that she appreciates the absurdity of her situation and is able to treasure some good times in the midst of the overall insanity.
How does humor come into play in your stories. Do you prefer your drama straight or mixed?