Is anyone else depressed by Lauren Grahams performance in Parenthood?

I'd like to start off by saying I LOVE Lauren Graham. She caught my attention with her sarcastic wit in Gilmore Girls, one of my favorite shows. When I heard she was in the new series Parenthood, I was elated. I have only watched a few episodes, but so far I am extremely disappointed in her character. She seems so serious and depressed. I have yet to hear her crack a joke. Did I miss some of the humor or amusing episodes? Opinions please.