When I was at Uni, I used to listen to Express yourself before an exam. They all went very well!
In 2007 I faced a very dark period, I was heartbroken, I hated myself, and I can really say that the release of Hey You saved my life. I know many don't like that song, but it really helped me to go on and to hold on.
In general, I find that You'll see is one of the most motivational songs. Maybe because I was never able to find a true partner in my life, so I can relate to the lines "all by myself... I know I'll survive" etc.