The book uses a lot of metaphors, which are implied comparisons without using "like" or "as." For example:
* "I felt like a fish out of water." This is a metaphor, not a simile, because it's saying he felt *like* a fish out of water, not *like* something else.
* "Greg's plan was a disaster waiting to happen." This is also a metaphor, comparing Greg's plan to a waiting disaster.
There are also moments of idiomatic expressions that may sound like similes, but aren't:
* "He's been acting like a total jerk." This is an idiom, meaning he's being rude and obnoxious. It doesn't directly compare him to anything.
While similes aren't a key feature of the book, they do use a lot of other figurative language that adds to the humor and helps readers connect with the characters' experiences.