Diary of a crazy sister and a crazy brother

This cool diary with action-packed illustrations is amazing in that there is not just one, but two - a girl named Olivia and a boy named Oliver, who are almost 9-year-old twins. It clearly shows that a girl just has a completely different view of the world than a boy, sort of by nature. Even if my sister is a "dumb" and sometimes her walking is not bearable, and even if my brother is a "smelly asshole", there are still times when they both have to pull together.