From Eric Barker's article:

And friends make you happier than pretty much anything else in life.

Got three friends at work? You’re 96% more likely to be extremely satisfied with your life.

Happiness is contagious. Happy friends boost your chance of happiness by 15%. Unhappy friends decrease it by 7%.

Each additional friend means two fewer days of feeling lonely every year.Family members don’t even move the needle here.

Via Friendfluence: The Surprising Ways Friends Make Us Who We Are:

If you can count at least three dear friends at the office, you are 96 percent more likely to be extremely satisfied with life in general…

Fowler and Christakis found that you are about 15 percent more likely to be happy if one of your friends is happy (overall, not in any particular moment). Even if a friend of your friend is happy, you’re 10 percent more likely to be in a contented state. “We found that each happy friend a person has increases that person’s probability of being happy by about 9 percent. Each unhappy friend decreases it by 7 percent,” they write. Since these stats imply that happiness is more contagious than unhappiness, they conclude that “the more, the merrier” holds true, despite what is usually said about quality over quantity in friendships. They also found that an additional friend amounts to two fewer days of feeling lonely each year. “Since on average (in our data) people feel lonely forty-eight days per year, having a couple of extra friends makes you about 10 percent less lonely than other people. Interestingly, the number of family members has no effect at all.”

Having a friend you see on most days is the happiness equivalent of an extra 100K a year. 

Via Social: Why Our Brains Are Wired to Connect:

…having a friend whom you see on most days, compared to not having such a friend, had the same impact on well-being as making an extra $100,000 a year.

Read more: http://bakadesuyo.com/2013/11/how-to-make-friends-easily/

Notes about that article:

http://pandawhale.com/post/31064/how-to-make-friends-easily-and-strengthen-the-friendships-you-have

http://pandawhale.com/post/40459/why-a-compassionate-corporate-culture-matters