One of the few things that can be more difficult than parenting is parenting somebody else's child. It's fair to say that parents have widely differing standards when it comes to how kids should behave, and how to deal with it when they're being difficult.
Many moms and dads have had disagreements with how caretakers interact with their children when they aren't there, and often it is completely justified. Other times, though, the case is less clear-cut.
This was a predicament that one Redditor recently suffered when he was looking after his niece, along with his own kids and his wife's cousin's children. He tried to order pizza for them all at his niece's favorite pizza spot, but had to cancel when the order hadn't come through after ninety minutes. The niece promptly threw a tantrum when he ordered pizza elsewhere, and insulted the food when it arrived.
As a result, he told her that she would have to eat leftover chicken pasta instead of the pizza they had ordered. His sister-in-law protested greatly when she came to pick up her kid, but it's fair to say that Redditors could see his point of view.