“Hi! My message is maybe weird, but I had to tell you: you are an incredible musician.
I saw you twice in Stockholm last weekend, and I think I could've listen to you for hours and hours.
Anyway, I know that sometimes this kind a career could be tough, not much compliments for all the work you should put in it, so I thought that maybe this little message could make you feel happy.
So good luck for everything, keep going that way, your talent should be heard everywhere!”