I found a really great article in Atlantic on the theme of passion.
I want my students' parents to read this article. When things get difficult or boring, don't let them drop music lessons too easily. Don't tell your kids "follow your passion" or "OMG, my kids are soooo talented!" If you keep saying that, pretty soon, that is all they try to find. "My mom is so happy when I perform, especially if i'm playing something flashy." Instant gratification is like a drug. The louder the praise, the more they will try to find flashy, popular pieces to perform which may not give them technical proficiency over the long haul. However, music is not always exciting. Music is not about being better than anyone else. Music learning is like excavating a beautiful jewel in the deep cave. You got to crawl, take a long, arduous hike, take a wrong path, head back, then start over again. It takes decades. Naturally, it is a life-long pursuit. You should ask yourself, "Am I ready to do that with my child, and never to give up?"
Most of my young students drop lesson after less than a year because of this damn wrong notion. No so much with my older students. The study itself, as with any other worthwhile pursuits in our lives, consists of mundane, tireless work. Adult students have learned this quality through their life experiences. But not those small children. By fanning the unnecessary flame of so-called passion, you are taking the attention away from the art of learning how to read and write and listen.
Passion can be found after many years of trial and error. Don't emphasize it first. Just keep the piano lid open, set the daily schedule, gently praise if your child did his homework. If your child said she hated the piano, don't overreact to it. Don't encourage your children (or yourself) to seek for a spotlight on stage too soon or give excessive praise. What you should give your kids is balanced encouragement that is somewhere between complete indifference and Tiger Mom. Being cool is not the same as being cold.