This mentality comes from a place of privilege and a gross misunderstanding of human nature.
It is incredibly easy to sacrifice a night out or a tasty treat when you have money. It's easier to sacrifice when you know that if you really wanted it, you could just get it tomorrow or next week.
People trapped in poverty don’t have that peace of mind. If they don’t treat themselves today, they may not be able to treat themselves again for a few weeks or months
Never enjoy anything ever is not realistic advice for the middle class trying to dig themselves out of debt or get their financial lives on track either. People aren’t machines. We need some treats and basic comforts every now and again.