Personally, I think there are two situations. Some people's temperament is born, and some people's temperament is cultivated.
Acquired temperament: this is the most common. Being born in a good family, you can receive a good education and accept the influence of art from an early age, but the premise is that you should "cultivate from an early age". It is not that people want to cultivate until they reach adulthood, but only play a role in improving. But this is almost only applicable to children with good families. It is almost impossible for children born in ordinary families to have good temperament. Family environment is related to parents' personality. Children are parents' mirrors, and what kind of parents have what kind of children. People's temperament is directly related to their parents' education.
Natural temperament: this is rare, even rare. Some children are very temperamental when they are very young, without any training. Because of the distinctive and rich inner world, elegant personality, modest connotation, rich hobbies, some views on art and lofty and meaningful dreams, all these can make a person have his own unique temperament.
Temperament is really important to a person.