Shower in peace

Why is it that your children can play on their own for atleast 5 minutes until you want to go to the bathroom or shower? Then within seconds, it seems like they are banging on the door wanting you out!! I came up with a plan to have some toys only be for when I shower, that way they would stay semi new and hold their attention better than their toys they can play with all day long.
I got a few toys from around the house and one new one and put it in my closet on the "shower toy shelf". The toys have varied from a cash register (then I gave my daughter a pile of books to scan), flannel board pictures, cooties game, and all of her food and dishes. This kept her from banging on my door (unless she had a potty emergency) and I was able to shower in peace. It worked for me! Good Luck with it. What are some things that have worked for you? Or has anything worked? :)