The time when Maria had drawn a picture of Ben and everyone agreed that it was hauntingly true to life and really captured his soul. When we see the actual painting it fails to live up to hype and a text blob appears saying: "Yeah we know it doesn't look much like him. Just go with it."
Pretty much every single fantasy/dream sequence.
The one that takes the cake though is when Annie has a nightmare starting with her and Gregory in bed. Suddenly Olivia pops up to start spilling Annie's secrets, and as secrets come out the people affected by them (Cole, Caitlin and AJ) also pop up in bed. AJ then requests to have a private conversation with Olivia - in Annie's fantasy.
Cole: I can't believe it. Caitlin's right, she does talk out loud to herself. She really is crazy. Wait a minute. Why am I talking out loud to myself?
Baby Trey and the family dog having a Look Who's Talking style conversation at Christmas, summarizing everything that's happened thus far in the season. The dog wishes he belonged to a more normal family, "like that dog from 7th Heaven".