From my “Murphy’s Law” desk calendar archives thanks to Aunt Evelyn, Uncle Pipey, and cousin Nancy:

Denniston’s Law: Virtue is its own punishment.
Denniston’s Corollary: If you do something right once, someone will ask you to do it again.

Goofy guy’s addition to Denniston’s Corollary to Denniston’s Law: …and again and again and again.