Look at these guys. I could never have played in ELO because my hair doesn't get all frizzy when it grows out. On some level, I can't really relate to this song, because I've never been that uncomplicatedly happy in my life. I'm not sure any human has. This song is so happy I'm about 90 percent sure there's some darker meaning, like Jeff Lynne wanted to kill his wife, and "Mr. Blue Sky" was the code name for a hitman, but I can't find any.
But really, this is a matter of establishing a familiar melody for both the verse and the chorus--which is simple, and is about being happy the sun's coming out--and then making it feel like it's going to go away, then bringing it back, the way you'd play peek-a-boo with an infant. And the rhythm section definitely gives the impression that you're being bounced on someone's knee.
This is the song you'd get if you took a tune you couldn't get out of your head and sang it to 12 or 13 talented musicians, then locked them in a room with classroom instruments for eight hours. Because there's so much going on here, and all of it is light and fun and whimsical. It's musically complex but spiritually uncomplicated. To know "Mr. Blue Sky" is to not only to know the lyrics and melody, but the countermelodies and harmonies and string parts as well.
This is what happiness sounds like.
This is what happiness sounds like.