In earlier seasons Matt was dating a deaf girl named Heather at the start of the the relationship they communicated by sign language and written messages but after a date Heather reveals that she can speak but often doesn't because people make fun of the way she talks. After she leaves, a stunned Matt remarks that he thinks it's the most beautiful thing he's ever heard.
Rev. Camden adding a picture of of Robbie on his desk next to those of his wife and biological children, showing how he considers him a part of the family.
Lucy's birthday present to Eric in season 5: Telling him she wants to follow in his footsteps as a minister.
Kevin proposing to Lucy at an elegant dinner, in front of the entire Camden family.
Say what you will about the sudden eleventh season after the show's hyped finale, but the true final episode of the series is pretty sweet. Especially the final moments in which the family piles into the RV with their things and invites a recurring extra along for their road trip.