In mosts flavors of photography, but especially in journalistic and street photography, chance can be, and often is the deciding factor.
Sometimes you just can't guarantee the shot will be there; sometimes everything may align as you want, other times it never will. That's the beauty of spontaneity; you, as the creator, have to simply deal with it.
But you take the chance; set up the shot, choose the correct shutter speed, the right aperture. You think about the light, the motion. You focus the camera. You take the chance. Go with it, no matter the outcome.
If you didn't take the chance, there'd be no photo. Neither a bad one or a good one.
Take your chances, do what you can't do. Explore the boundaries; realize they're not absolute. An opportunity missed makes a less interesting life.
Don't be boring, please.