"It didn't make sense not to live for fun,
your brain gets smart but your head gets dumb"

Smash Mouth - it's on my Shrek soundtrack!

OOh - and that one from The Proclaimers -
"I'm on my way, from misery to happiness today,
uh-huh-uh-huh-uh-huh-uh-huh,
... and now that I don't want for anything,
ooh-ooh-ooh-ooh-oh,
I'm sitting on top of the world"