From Your Five-Year-Old: Sunny and Serene by Louise Bates Ames,and Frances L. Ilg (okay, the language and some of the content is really sexist, but its great stuff and the pictures remind me of when I was growing up as these books were written in the '70s):
What can you as a parent expect of you Five-year-old boy or girl? It is a pleasure to tell you that with most Five-year-olds, some very good times are ahead. Five wants to be good, means to be good, and more often than not succeeds in being good.
Perhaps most delightful of all his characteristics is that he enjoys life so much and looks so consistently on the sunny side. "Today is my lucky day," he will tell you as he jumps out of bed in the morning. Or, enthusiastically, "Today I'm going to do all the good things and none of the bad things."
Even his language is on the positive side: "Sure!" "All right!" "Fine!" "Lovely," "Wonderful" are among his favorite words, and "I just love ____" is a constant refrain.
The key toa ll this goodness may be that for a few months at least, Mother is the center of the child's world. He not only wants to please her, he wants to be near her. Wants to talk with her, play with her, help her with her housework, follow her around the house. Many Fives would actually rather stay in the house with Mother than go out to play with their friends.
. . .
Five, by nature, is quieter, more pulled in, closer to home. He not only prefers to stay ithin prescribed boundaries but feels most comfortable wtih the tried and true. The time that interests him is now; the place he likes beset, here.
Unlike the child of some other ages, Five often shows a remarkable ability to protect himself from overstimulation.
Five is usually not a worrier. . . He likes life the way it is, satisfied with himself, and adores his parents.
Now for the following six months: the other shoe drops.
So here you are, sailing along, happy as a lark. Your little son or daughter for almost six unbelievable months may have been good as gold. . . . Thus it can be more than a little disconcerting when all of a sudden things aren't so rosy any more. That little angel who responded oh, so easily, with "Yes, I will," now is quite likely to say "No, I won't.". . . Quite possibly, no more than the beginnings of Six-year-oldness, a time that often brings trouble into the calmest households.