4. Lasting friendships encourage more birthdays
Close friends could be the secret to longevity. When older adults have close confidants, they're likely to live longer, according to a 2005 study conducted by Australia's Flinders University. After following 1,500 people for 10 years, researchers discovered that people with a large network of friends outlived their counterparts by 22 percent.
Other studies touting the health benefits of friendship have shown that friends lower the risk of disease by reducing blood pressure, heart rate, and cholesterol. So while it may be tempting to think that friends are sometimes more trouble than they're worth, clearly, having close friends can be one of the best things you can do for your health.