Can you be happy for 100 days? Itâ??s a challenge sweeping social media.The website says we live in a world filled with "super-busy schedules." In an effort to get more people to "appreciate the moment, the environment and yourself," the website is encouraging people to try and be happy every day, for 100 days.Wondering what you have to do? Well, first register on their website 100happydays.com . Then all you have to do is post a photo on Facebook, Twitter or Instagram every day, for 100 days, with #100happydays. The photo can literally be anything that makes you happy from favorite foods to being out with good friends.Although it sounds easy, the website claimed 71 percent of people actually failed to complete the challenge. But the website also noted that people that did successfully complete the challenge started to realize what makes them happy, how lucky they truly are, and become more optimistic.