Anyone can think “inside the box” it doesn't take much to come up with an idea that's already been thought before. But thinking outside the box? That's a challenge. That means taking risks. That's how progress is made.
Don't worry about making mistakes or taking risks when thinking outside the box. Think outside the box when you have time to make it a reality. We'll all have plenty of time to come up with mediocre ideas when we're dead.