Because of the natural egoism, the feeling of omnipotence and the unlimited demands of the infant, ingratitude can be looked upon as an original human state of mind and 'the fact that grateful people do exist proves that pedagogy is not as hopeless a task as some pessimists assume'. Ungrateful people are not only those who have remained infants in this respect but also people who, throughout life, are occupied with taking revenge for not having gotten everything. Whatever they get 'is compared inwardly to the alleged lack of love, attention and kindness about which the beneficiary inwardly grieves'. Several special types of ingratitude are discussed in detail.