I knew you'd choose the wrong one The best moment in the entire series comes near the end of this episode.
The episode plot entails a bomb being found in Stalag 13. At first, Hogan thinks it's a fake, built by Sgt. Carter.
After he realizes the bomb is real, and ready to explode, Hogan has to choose between two wires to cut to defuse the bomb. Hogan asks Colonel Klink which one to cut: one wire stops the timer, but cutting the wrong one will blow up the bomb.
Klink picks a wire, and Hogan cuts the other one. Klink says to Hogan, "If you knew which wire to cut, why did you ask me?"
And Hogan answers, "I didn't know which was the right one, but I knew you'd pick the wrong one.
This encapsulates Klink's ineptitude in such a marvelous, funny way.