I really like this song, even though I'm not a usual fan of Katy Perry. I think it is just good, with a good message and a good feeling.
I chose this video because her music video is, not gonna lie, totally freaky and bizarre. It tries to be uplifting and encouraging, but I think they pulled only minimal success through that forest of flash, shock, and misdirected creativity. Plus this one, you get to see the words!