Timmy's parents come to the conclusion that wherever Timmy is, he's watching television, so they preempt every show on TV to deliver the message that they were wrong and that they love him. As soon as Timmy sees, he immediately leaves the TV for good.
If you look closely, one of the channels they preempt is showing the Dimmies, the Dimmsdale equivalent to the Oscars. Timmy's parents preempt the Oscars to get their son to come back!
Timmy twenty years in the future looking back at a picture of his goldfish and smiling.
No mention of Cosmo and Wanda being the Oddparents of Timmy's kids? Specially Wanda's nostalgic comment at the end.
Wanda: Like father, like son?
Cosmo: Tell me about it!
The simple fact that Timmy would rather put up with Vicky for another 8 years than lose his fairies, since she was the main reason he got them to begin with. Cosmo sums it up beautifully.
Cosmo: Wow! He loves us more than he hates her! And that's saying something!
The first thing Doug Dimmadome remembers about Timmy is that Timmy found Doug's missing son Dale.