I have two:
1) When Ross and Rachel are arguing in Season 3, about him sleeping with the Copy Girl, and Rachel says, "I always thought you was the one man that would Never, Ever, hurt me..."
2) When Mr. Heckles dies in Season 2, and Chandler says to his empty apartment at the end, "Goodbye Mr. Heckles... We`ll try and keep it down."
Charlie.