When we looked at our Boston newspapers this past Thursday, a cavalcade of headlines, one-after-another, told stories of sadness and tragedy throughout our area. There was the four year-old boy who was struck and killed by a hit-and-run driver in Hyde Park; the brothers who died in a single-car accident in Brockton; and the 11 year-old daughter of a former New England Revolution player who died in a boating accident in North Carolina. Saturday brought more tragedy — a 21 year-old man who died while swimming in a lake in Hopkinton and a 17 year-old girl who died in a boating accident on the Cape. These incidents remind us how precarious our lives, and those of our loved ones, can be — and how life can take a turn for the tragic in just the blink of an eye. Accidents are the leading cause of death for young people in our country. Safety for ourselves and our loved ones never should be taken for granted and always must be our first priority in everything we do.