I don't think heart and ego are all that separate. I sing songs I love. I sing them to share what it is I love about them with others. When I sing songs like this, I think I'm much better than if I sang songs to show off. (Not that I could anyway.)

When you share your passion for a particular piece of music, you ARE a better performer. It's good for the whole person, not just their ego, and it's good for those who listen. Learn the technical skills you need to express the music of your heart, but let your heart be the most important thing.