The Spaniard, who is now in charge of Bayern Munich, managed Barca between 2008 and 2012 – winning three league titles and two Champions League crowns.
However, he has claimed that it became difficult to 'motivate himself' in the final stages of his tenure.
"We were incredibly successful - 14 trophies in four years. But that can also weigh you down," he told Super Deportes.
"I was having difficulty motivating myself as well as the team, having won everything as a player and a coach. And the team was finding it increasingly difficult.
"The sabbatical year in New York was important to me, my family and to my old team."
Guardiola also won the La Liga title six times as a player for Barca.