Because I like it almost as much as season 5! :D (And I don’t think season 5 needs an explanation; I think it’s a favorite to lots of Mondler fans ^^) I like Mondler in season 9 a lot and that’s a big factor, since Monica and Chandler are my favorite characters.
I love the way they both look in that season; in my opinion, Courteney and Matthew both look really good in seasons 9 and 10. I liked the way they looked individually in several other seasons, but in those two seasons I like both of them equally.
But the most important reasons were their storylines. They had their ups and downs during that season. We saw them fight and make up, we saw them have difficulties and also have fun, we saw them love and support each other as always. They were trying to have a baby and at the end of the season they were both at the same page, matured enough (especially Chandler who hadn’t really been ‘there’ before) to know exactly what they wanted and dealed with the unfair situation life threw their way together. They had already been married for over a year and they seemed to be more settled to their life as a married couple. They also had their funny moments. I just really love season 9 Mondler! :)