On the one hand, most children stay at school an average of 8 hours. They do all the activities that a child has to do in his/her daily life, 4 hours studing, 2 hours in the eating room, 2 hours doing other activities with their classmates or individually (for example sleeping).
On the other hand, the child spends a short time with the family, inside or outside the home, with a total daily time of 4 hours. In addition, at least, one of the parents usually works all the day and consequently, he comes back home tired and he doesn't pay enough attencion to his son/daughter.
All in all, school might seem more important in shaping a child's personality. However, a part of a person's personality is geneticaly determined when hi is born and he develops it during his experiences in school and at home equally.