The same thing that's wrong with aspiring to have "zero bugs" in a codebase. You can have zero open issues (redefining "bug"), or zero known bugs at release (JPL-level quality metrics, at a huge cost), but any reasonable software developer knows that bugs must be accepted as part of the process of coding. Similarly, humans must accept that "accidents" are part of living. Things are not and never will be perfect, no matter how many rules or systems or metrics you put in place.