I can’t choose one.  Here are a few.

• Illya getting kidnapped on a red London bus in New York (that whole episode was wonderously mindfuckery) (I should include it all) (especially Edith Partridge)
• “Well, I never wanted to be impregnable” (hahaha, Napoleon really didn’t think his question through)
• Victor Marton visiting Waverly
• Illya of Arabia leading a cavalry charge (I have a serious lifelong crush on Lawrence of Arabia)
• Tavia Sandor and Illya gazing at each other (Evidence that Illya CAN show spontaneous interest in females yay!)
• Soaked and torn black t-shirt O.O
• Illya and Napoleon’s fake fight to help Napoleon escape
• Waverly getting an as good or better score on the firing range than either of the boys, without using a sight like they did
• Lisa Rogers revealing the contents of her purse, indicating that she had used the anti-agression spray mostly outside of the line of duty and suddenly Napoleon looked REALLY uncomfortable. (You go, girl.)
• Napoleon’s threat to Mandor
• “We have each other”