Pursuit of Happiness by Kid Cudi: a mellow, yet upbeat song for a happy mood.
Pursuit of Happiness, like a lot of the songs on this album, has a very mellow feel. The beat is so catchy that it makes you want to sing along and even if you're not in the mood, it somehow picks you up and has you feeling good again. One line really sticks out, "You don't really care about the trials of tomorrow." This is basically a demand to stop worrying about everything and just feel happy for a change. I play this song whenever I'm having a stressful day, and I end up being picked up, and even inspired at times.