Melanie Klein said this quote

“ Although psychology and pedagogy have always maintained the belief that a child is a happy being without any conflicts, and have assumed that the sufferings of adults are the results of the burdens and hardships of reality, it must be asserted that just the opposite is true. What we learn about the child and the adult through psychoanalysis shows that all the sufferings of later life are for the most part repetitions of these earlier ones, and that every child in the first years of life goes through and immeasurable degree of suffering. ”