Cullen departed the former European champions this year, allowing them to sign-up his former All Blacks team-mate Doug Howlett.
But he does not yet feel he missed out by retiring at 33 years of age.
"I guess the people and the country were a good experience, but the rugby was a bit different," he told The Manawatu Standard.
"But I don't miss training during the week. I'm getting a bit old for that. The weather was a big thing and when you get back to New Zealand, you know nothing beats it."
Cullen was part of the 1999 World Cup side undone at Twickenham by France and felt sympathy with his successors eight years on, after their defeat in Cardiff.
"We had the best side at the World Cup, they just had a bad day and maybe were a bit underdone - didn't have the tough games they needed as a team, from a year together," he added.