> Our idea targets young people (12-25 yrs). Which leads to my thinking, that because they're unfamiliar with it (YC partners too old, would never do facebook quizzes), they brushed it off?

Did you validate your ideas somehow? Maybe some surveys or examples of existing similar apps being successful? Any prototypes?

It is easy to say YC partners didn't get your idea - but it was your job to demonstrate that it holds real value.