The simplest and most insignificant victories inspire the feeling of self-esteem.
The victories can be as insignificant as the victory in a game, the smart reply to somebody else, the skillful fixing of a small damage into the house, etc. Beside, many of them are reached when we are alone, so that we cannot say that we prevail against somebody else.
Therefore, the self-esteem acquired in this way escape from an objective criterion and from the compulsory social standard to evaluate our success comparing it with that achieved by other persons, sometimes by defeating them.
It is a subjective self-esteem. In other words, it is the pleasure of feeling that we raise ourselves during a lifespan which can be designed according to our person only a little.
We may imagine that the other animals have the same feeling when they eat or get their mates. They are also small victories for an outer observer.
The peculiarity of human species is to make further claims on the basis of such small victories. We easily forget the trivial source of our feeling of self-esteem and dream about future greater victories. When the dreams were fed by those small victories, the greater ones are pure illusions.
Sometimes, the society helps us to consider that the small victories can become greater. It praises great gamers, clowns or comedians who have a lot of smart replies at their disposal, the most skillful masters of small things, and so on. However, such cases show that the society as a whole is defective in finding another form of self-esteem than those small victories. The small victories continue to be small.