"Dear Diary" is an episode in the first season of LazyTown.
"Robbie Rotten forges some pages of Stephanie's diary and shows it to her friends in LazyTown. They are very angry at Stephanie for writing nasty things about them. Stephanie doesn't understand why they are so upset but, with encouragement from Sportacus, Stephanie shows them what is really in her diary. Everyone has a change of heart, even Robbie."