I recently stumbled across a YouTube video, where a UI person is showing a mock up of a children's website. And he's showing this to a girl who is maybe five or six years old. This is essentially what we would call as a user study. However, without the digital knickknacks there was something very special about why he got amazing feedback.
Now unfortunately a lot of us spend a whole lot of time and energy and effort in the journey leading up to the prototype. We are so convinced in our processes that we end up creating the best prototype possible. It's almost as good as the finished product. However, we have ignored the user in a lot of these cases. You have left these huge blind spots. And the real user feedback can often come crashing right into into you.
That's where a lot of startup journeys also end, because they've given it their all in creating an amazing prototype, but one that did not resonate with their users. So prototyping has to be fast. It has to be cheap and you should try to get the user talking to you in the first place. Best of luck.