"Trouble is a Fire" by Arisato Chika (not pleasant, but very nice, suitable for background music)

lenka's "Trouble is a Fire"＇"the show" 》(This one best meets your requirements)

The background music of "Castle in the Sky" is a classic among classics!

Avril Lavigne's "Innocence" is very suitable for background music. Not very cheerful.

The above are all English songs. I would like to use English songs for the background music, so as to have more feeling. Little is known about the pleasant ones, which are either a little sad or very sexy, like Britney's. The recommended songs are all old songs. You should have heard them all. I hope you like them.