Here’s the Cringe book webpage, which says:
We’re looking for brave souls willing to share their old diaries, journals, letters, notes, songs, poems… anything you wrote during the crushing misery of adolescence and then saved in a hidden box at your parents’ house all these years. Top secret no more.
The more dramatic, embarrassing or excruciating the writing, the better. A good test to determine whether or not your material is Cringe-worthy: when you read it to yourself, do you physically cringe? Then for the love of god, it needs to be in this book. Seriously. You are going to be so glad you did this. Cheaper and better than therapy.