This is a very difficult question and its hard to single out just one particular song. I love so many of them and I gave this quite a bit of thought before deciding. If you think about how many great bands there have been even in the last 30 or 40 years and how much music has been produced, picking one favorite song is a monumental task. If you ask me my favorite song on any normal day you'd have to narrow it down to a certain genre or even an artist, and then I might be able to pick one. But since I am only allowed one choice, it is going to have to be ABBA. I am not sure if this is my absolute number one favorite song but it is definitely one of them
I love ABBA but their music videos are a little horrendous. So don't mind that visual part so much as the actual song. This song is a little depressing but a little cathartic. It's empowering but at the same time a little dark. Not only is it sweet and beautiful, it also has the haunting, heart wrenching tragic aspect that makes it so great.