The results of a 15-year study from Psychology and Aging can pinpoint the exact moment at which you’d best get off an old man’s lawn. The study found that most men tend to get generally happier as they get older, as life slows down and security sets in. However, something shifts when men hit 70, and they start getting grumpy. The study was unable to determine exactly what happens at age 70, but declining health and loss of loved ones were both cited as possible reasons men’s moods shift. Of course, grumpiness isn’t pleasant, but it has its upside. “At least one study found that older men in nursing homes who were grumpy actually lived a little longer,” Carolyn Aldwyn, a gerontology professor at Oregon State University and the study’s lead author told NPR. “The thought is that these individuals could voice their unhappiness with their current situation and perhaps get more attention and perhaps better service than individuals who suffered quietly” …