I downloaded the Phineas and Ferb soundtrack album (available on iTunes) and listen to it a lot. It's amazing how many good songs in such a variety of genres they can come up with. Ok, some are silly, but it's a great album and the kids like it too. I admit, I love that show. There is so much good about it, and it's been written about extensively, but the expanded theme song, "It's Gonna Be a Great Day" by Bowling for Soup, is a wonderful philosophy for life.
Here is the song, although the person who transcribed the lyrics made a few errors.
The chorus is fantastic:
"This could possibly be the best day ever.
And the forecast says that tomorrow will likely be
a million and six times better.
So make every minute count.
Jump up, jump in and seize the day.
And let's make sure that in every single possible way
Today is gonna be a great day!"
Seriously, go back and read that again.
Now go do it.