In short, the money we didn't work hard for is easy to spend, but the money you know you worked hard for is sure to be valued truly and rightly. There is the feeling that you will value every single cent of it.
That's true and I think not only about money, but almost everything like that. Because what is obtained easily or for free will more often than not be well appreciated by anyone, while what is obtained with difficulty will always have better value and price and will even be looked after quite well when it is obtained. When it comes to money, most people will be more frugal when they get it harder, but money given to them by their own parents or other people will tend to be easier for them to spend on many things.
That's why every hard-earned income should go to meaningful things. If you want to gift yourself, it's normal, in my opinion, as long as you take the consequences, whether you're going to do it for good or bad purposes.
I quite agree that every penny or money earned the hard way must continue to be appreciated for things that are meaningful and for important needs in life. Because the consequences are also quite clear if a person does not value the money he has well enough for himself, he will be more easily hit by difficulties when the money runs out.