Why does it bug me when people use the phrase "my muse"? I mean, there are nine of them. Why can't someone have a personal one?

Oh, wait. BECAUSE WE ALL HAVE TO SHARE THOSE SAME NINE. So, you don't get to have one of your OWN. Unless you're selfish. Which I am. So, I choose Melpomene. She's MINE. You can't have her!