In the two-part Season 6 finale, Chandler tries to convince Monica he doesn't like the idea of marriage so she won't see a proposal coming. Instead, it makes her rethink her relationship with Chandler and consider going back to Richard.

But in the end, when Chandler thinks he has lost her for good, he finds her in their apartment, ready to propose to him instead of the other way around.

When she stops midway through because she is crying, Chandler takes over and finishes the proposal. It was one of the shining moments of their relationship arc on Friends and finally banished any fans' concerns that Chandler and Monica wouldn't last, given her past relationships with men like Richard (who was easily a fan favorite).