For the record, "Best dancer ever!" was the line that I had to stop the screener DVD for because I was laughing so hard. Couldn't restart it for about 5 minutes.
I think it's not the line in itself, but the pile-up of really funny stuff before it that primed the pump. It was a build-up and that line just opened the floodgates.
Anyway, I also like how they kind of set this episode up as a throwaway bit in "Dial M for Mother" (when Trinette tells the German assassin that "his daddy knows Krav Maga").