Sorry is the hardest word, but for Jennifer Lee, director of the Disney film Frozen, it’s one she’s having to say over and over again. The animation and its intensely catchy songs – once described as “musical crack” – proved an instant hit when it was released at the tail end of 2013, and parents congratulated Lee whenever they saw her. A year on, however, her reception is very different. “Now [the parents are saying] 'Yep, we’re still listening to those songs’,” she told the Hollywood Reporter. “I’ve gone from, 'Thank you’, to, 'Sorry’.”