The home videos from before Katie died; whatever Mike's flaws, it's clear that he loved the hell out of his daughter. Unfortunately, those same home videos are only the run-up to Mike being repeatedly psychologically kicked in the nuts later on.
When the room tricks Mike into thinking he's escaped, Mike attempts to reconnect with his ex-wife, Lily. It's pretty heartwarming seeing him try to reconnect with the woman he left due to Katie's death.
Mike attempting to reconnect with his father in the deleted scenes, showing that despite his attitude early one, he still loved his old man.