Lyric discussion by nineteenfiftyfour 

This song is about being in a place of horrible emotional pain or depression, but with the reassurance that things will get better. The audience is the piano, a metaphor using imagery of classic beauty (like the waltz) -- it might feel worn out and hurt, but it can still produce a waltz in its heart inside, through three beats -- and it's not useless/garbage/ready for destruction/firewood yet. "And nothing can stop you from dancing" means that no person who caused this pain can stop you from recovering and coming out on the other side a stronger person. Yes, it's going to hurt to go through the healing process, but all processes have a beginning and an end. It may seem like life is terrible right now, but there will come a day when you will take the calendar/clock of your life down off the wall and wish it hadn't all gone by so quickly. You will love again, though nothing can prevent that love from not lasting forever either, and the cycle will start again.

I was about to post EXACTLY what you typed.

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