Storytelling in general is a communal act. Throughout human history, people would gather around, whether by the fire or at a tavern, and tell stories. One person would chime in, then another, maybe someone would repeat a story they heard already but with a different spin. It's a collective process.
Joseph Gordon-LevittFor context, the budget of Don Jon is about half the budget of (500) Days of Summer. And (500) Days of Summer is about a third of the budget of the lowest-budget movies produced at a major studio.
Joseph Gordon-Levitt