I have just read something both incredibly mind-blowing and incredibly intuitive (as many mind-blowing things are) : Having strong relationships and friends that you can confide in can increase your life span more than quitting smoking!
So, just imagine the emphasis everyone puts of quitting smoking these days. These days, smoking is treated like a contagious disease. No one wants it near them and so many people judge smokers as harshly as any criminal. The primary complaint that people have is that it is wildly unhealthy, which it is, but so is having meaningless relationships, or no relationships.
It's easy to publicly acknowledge that someone smokes because you can't hide it very well and really, it's largely just affecting you (unless you're not a very considerate smoker who blows smoke right in people's faces). But even though you can identify (usually) when someone has no friends, we know instinctively that it is an awful fate that no one would wish upon another. It's so awful, we can't bear to acknowledge it publicly.
So, if you've been thinking that you'd like to see some positive change in your life, go make some friends. Say hi to a stranger, help someone out or call up an old acquaintance. It will serve you far better than just about anything else you could do for yourself.