I rarely shed a tear watching TV, but this episode gets me every time. Everyone gives Klinger a hard time because he is no Radar. It takes a talk with Col. Potter (with help from Father Mulcahy) to make him realize it took Radar time to become great at his job and make it his own.
BJ is upset when he reads a letter from his wife Peg saying how great meeting Radar at the airport was. Erin called *him* 'daddy'. This really upset BJ because he was missing seeing his baby girl grow up. When he left her she was a baby and now she was talking --- and calling other people 'daddy'! The saddest part, as he tells Hawkeye, is it doesn't matter if he goes back home soon. That time he could've spent with his daughter is gone forever.
It's an episode that makes you laugh out loud one second, and reach for the Kleenex the next. I'm 25 and this is one of the first episodes I watched and made me an instant fan.