I need a song that has strong emotions to dance lyrical to?

I have been dancing for sixteen years and will be graduating from high school this may. It is a tradition at my dance studio for the seniors to dance a "farewell dance" and I am going to perform a lyrical dance. The only problem is that I do not have a song yet, so I need help. I need it to have emotion, but yet still be calm. And it would be better if the lyrics were about saying "goodbye" or "thank you," but it's not manditary.