* Loyalty and friendship: Both Greg and Rowley are fiercely loyal to each other. They stick by each other through thick and thin, even when they are at odds.
* Naivety and innocence: Both Greg and Rowley are sometimes naive and innocent, particularly in their social interactions and their understanding of the world around them.
* Love of fun and adventure: They both enjoy having fun and going on adventures, even if these adventures often end up in comical mishaps.
* Desire for acceptance and popularity: Greg and Rowley both crave acceptance from their peers and are often driven by a desire to be popular. However, their methods for achieving this goal differ significantly.
Overall, Greg and Rowley's friendship is a strong one despite their differences. They complement each other, and their contrasting personalities often create humorous situations in the books.