Dr. Stanley Goldstein - Author and Psychologist

While focused concentration is prized, too great focus can be dangerous. Like when, obsessed by a personal concern, one incautiously crosses a busy street or, depressed by a recent job loss or romantic breakup, the person suicides. In these cases perspective is lost as tunnel vision predominates.
Yet tunnel vision, exaggerated narrow focus, can save lives too as when traversing a crime-laden neighborhood or on the battlefield. Unhelpful tunnel vision happens when the presenting situation is misperceived: as a permanent rather than temporary setback, and being perilous not innocuous.