Oh, I did not know that. Sorry :)
I want to say either David or Joan. David because he treats Elizabeth like complete crap sometimes and he's keeping all of these secrets that could really help everyone. He's actually been so hypocritical in season one. He knew that he had an affair with Lori way before Kyle and Elizabeth even started an affair, but he was ready to kick her out the door and humiliate her in his book. He just tries to play the innocent card to much and it's just annoying.
Joan because she just reminds me of my grandmother. She always has to give her two cents.