The way I (probably mistakenly) see it, the answer 42 represents a view of cheery perfection. It's almost as though it is trying to be as divisible as possible simply to be helpful. Even its name is annoyingly perky. It is the number which represents what the established order (notably religion) has told us represents the universe. It is the number of order, sense and reason. Neither 6 nor 9 nor 54 are particularly welcoming numbers. Douglas Adams seems to like this view of the world. Just like Sirius Cybernetics, we're sold the idea of something being perfect and flawless whereas we all know (even if we are reluctant to truly accept it) that the reality does not match it.
If you're into stuff like this, you can read the full review.