Like Pickle Juice on a Cookie by Julie Sternberg
Eleanor is having a bad August. Her very first babysitter she had since she was a baby is moving. Now she has a new babysitter who seems nice, but Eleanor just can't help being a grump. Without really noticing, Eleanor starts to enjoy her new sitter. August turns to September, and Eleanor heads to third grade feeling happy.
Recommended for grades 2-4.