“It was only until you were out of ideas and you asked yourself a rhetorical question and you came back with a sarcastic answer. And that’s what ‘Happy’ was,” Williams said. “How do you make a song about a person that’s so happy that nothing can bring them down? And I sarcastically answered it and put music to it, and that sarcasm became the song. And that broke me.”

Pharrell in an interview. So you’re right pretty much. It was created for Despicable Me 2 so the movie folks had veto rights and he couldn’t make something he actually would’ve wanted to make