Not necessarily. Sometimes, I don't want to show my notes to others because I am responsible for my notes or because I am protecting my privacy. Of course, if unwilling to show others notes brings great inconvenience or hinders others' study and work, then there may be some selfish elements. In this case, you can consider the conditions for showing the notes to others, such as making the other party promise not to copy or disclose them to others. Or, consider sharing your notes with others, but keep a copy of yourself at the same time. Personally, I don't think it is necessarily selfish not to show your notes to others, but it should not harm the interests of others. Before making a decision, you can consider other people's feelings and try to find a balance.

The notes themselves belong to personal privacy, and there is no requirement for compulsory sharing.

It is my duty to teach you a lesson. I don't want others to enjoy what I have worked so hard to sort out. This is normal, and I don't have to put too much pressure on myself. Besides, ability is also a competitor. It can be said that giving is generous, and not giving is the normal psychology of most people.