I struggle with how to teach my kids that they can and should have and feel their feelings, but also that they can moderate their behavior - that they don't need to have a huge melt down over every little thing, but they don't need to stuff their feelings either.
The old Free To Be You and Me song, It's All Right To Cry (see the youtube video) is a great resource -- beautiful pictures of people young and old crying, with the words "it's all right to cry, crying gets the sad out of you... "
Kate and I recently got another book about Little Rabbit from the library. Why Do You Cry? (Not a Sob Story) by Kate Klise and illustrated by her sister Sarah Klise, features Little Rabbit (from Shall I Knit You a Hat fame, reviewed earlier) on the eve of his 5th birthday. Little Rabbit assertst that he won't cry anymore, once he is 5, and only wants those who don't cry to come to his birthday party. Of course he finds out that all his friends still cry, and comes to see crying in a different way. This is a book we're going to buy.