The most influential thought-leaders had no agenda when they started out. They just wanted to educate.
The most successful inventors had no agenda other than to make life easier and simpler.
The most successful writers just wanted to tell the stories inside of them.
In this world wherein everyone (seemingly) has an agenda, it's nice to stop once in a while and do things without any motivations or hidden agenda—just doing something because we love doing it.
Besides, ideas without any other agenda spread better than those with.