What comes to mind when I say "musician"? Pop star? Symphony player? The band at a local club? There are others. How about your public school band or choir director? Or perhaps the musician(s) at your church.
A church organist is very busy right now. Not only providing music for Sunday services, but additional Advent services and perhaps a children's program. This requires a lot of extra practice and additional rehearsal time with children, choirs, and soloists. An organist doesn't have an organ to practice on at home so they need to go to the church to practice. That's additional time spent traveling and then arriving usually at a cold building.
Don't misunderstand. They do it willfully- gladly even. Oh they may grumble amongst themselves or at home - that's human nature. But they won't complain in front of you. Like "The Wizard of Oz" they don't want you to see behind the curtain. They work very hard in secret to make it look easy. That's the mystery of any productive artist. That it all happens by magic.
But it doesn't happen by magic, of course. It's a process of hard work punctuated with frustration at their own weaknesses and failings. And they agonize over every last note until that last note is played. And when Christmas is over they will take a few moments to breathe. And they will stop relaxing the moment they realizes that Easter comes early this year.