It's a warning that's on every box of matches and every bottle of lighter fluid. A simple statement of fact that fails to nail down just how horrible the consequences can be.
Carelessness causes not just fire, but pain and destruction. Carelessness ruins things one takes for granted, like a solid structure of a home or the confidence of a loved one.
Carelessness causes fire in places where the ill fated winds decided to carry it. Even with it's warning so cleary written on the outside, people who decided not to read the label closely will be burned.
Carelessness causes fire. Only by smothering that lack of attention, that lack of thought, it's the only hope we have in not ruining everything around us.