John: I'm going vegetarian once a week. Meatless Mondays! It's good for my heart, and my great grandma used to do that praying for my health. Maybe I can count it as a sacrifice in prayer for a friend's health.
God: NOPE. RESISTING MEAT IS GOOD FOR YOUR HEALTH, AND THUS SELFISH. YOU CAN'T PRETEND IT'S A SACRIFICE.
John: But my great grandma did!
John: ...What if I promise to eat really delicious fat-heavy meat once a week? Could you cure somebody's cancer then?
God: I'M LISTENING.