As a GM you are responsible of creating the environment, NPCs, their reactions, motivations, describing thing and countless other things. These are all about creating a story. You're not storytelling alone, but you're doing it, and it is bizarre to pretend otherwise. GM as some sort of impartial referee without creative input is not something that can exist in reality. So better just accept the role and the responsibility and do your best to craft a good story!
Also, the players are my friends, spending their free time with me, so of course I do my best to ensure that they have a good time!