It does take a certain discipline to put your own interest aside.
You can put your current desires aside for future opportunities (savings, for example), or you can put it aside in the interest of others (parenting, for example).
Heck, you might even be willing to fight a war over something like “freedom.”
The point is that some generations have understood a responsibility that was higher than “self.”
Another word for this is duty.
Self-respect is something that our grandparents, whether or not they had it, knew all about. They had instilled in them, young, a certain discipline, the sense that one lives by doing things one does not particularly want to do, by putting fears and doubts to one side, by weighing immediate comforts against the possibility of larger, even intangible, comforts.
-Joan Didion, Slouching Towards Bethlehem