When you play in your area of expertise, you effortlessly come up with amazing projects and ideas. Progression and skill development comes directly out of playing with what you are good at.
"Play is the highest form of research"
Not only does teaching further the person you are teaching, but it also increases your ability to communicate concepts. This skill is absolutely critical to perform in a team environment, especially when building software.
When throwing yourself into your work and pushing it to the end, a fantastic moment is created, one which fills you with accomplishment. You'll not regret working hard to polish and deliver the best.