5x12 - Supernatural

Some analysts suggest that Dean didn't immediately notice Gary (in Sam’s body) acting strangely because Gary was acting like the "fun" brother Dean misses—someone who would share his taste in music and go out for drinks without the usual Winchester baggage.

Beneath the humor, the episode touches on the recurring theme of the violation of Sam’s agency. Supernatural 5x12

Sam’s body is treated as a prize or a "meat suit" throughout the episode, mirroring the larger Season 5 arc where both brothers are viewed by angels and demons merely as perfect vessels (Lucifer and Michael). Some analysts suggest that Dean didn't immediately notice

The episode reveals a subtle, tragic layer to Dean's character. While Sam has accepted the hunt, Dean is the one becoming increasingly wistful for normalcy. Supernatural 5x12