Every time I started a rerun, I always began from s4 finale or s5 premiere because I love Monica and Chandler so much.
It's really hard to see a relationship like this on screen. They don't have dramatic on-and-off. It's not a prince charming history. It's not "you have to overcome all the difficulties to get your Mr. Right" type of relationship. As in Monica's words "I think that we fell in love and we work hard at our relationship. Some days we work really hard. "
Their relationship is so real, to a level that you cannot believe this is a "sit-com" romance. Yes they have a dramatic beginning, but I suppose a lot of relationships have a kinda dramatic beginning. And they tried, they were very careful, they cared until they were sure about each other.
Also, when you think about these two characters, they have almost opposite traits. Chandler is afraid of commitment because his parents divorced, but his parents still love him very much, and he didn't need to compete for his parents' love because he is the only child. On the other hand, Monica's parents have a passionate and stable relationship for decades, which makes Monica crazy about marriage and babies. But her parents favor Ross, her mom downgraded her, so she had to compete for everything in her life, and she got OCD. Monica gave out her unconditional love to Chandler and always supported him, so Chandler felt safe to commit, he felt safe to say I love you. And Chandler is willing to change for Monica's OCD and lose to her. They are perfect for each other. You wouldn't realize that until you look back at their relationship. Even before London, they just fit, you know they can stay.
And looking back to S1-4, I feel like they are always in a situationship. They flirt, they cuddle, they hold hands, they comfort each other, they seek safety toward each other, they share secrets, they share everything. They are always there for each other.
Words fail me, I don't have enough words to describe how much I love Mondler. They are just so good, so romantic, so sweet.