Calvin's mom and dad are mostly American middle-class parents; like many other characters in the strip, their relatively realistic and sensible manners act as a contrast to Calvin's childish and selfish behavior. Both parents go through the entire strip without names. They are only called "Mom" and "Dad", or nicknames such as "hon" and "dear." Watterson has never given Calvin's parents names "because as far as the strip is concerned, they are important only as Calvin's mom and dad." This ended up being somewhat problematic when Calvin's Uncle Max was in the strip for a week and could not refer to the parents by name, and was one of the main reasons that Max never reappeared.