"I want you to be happy day" is an unselfish day. Its a thought that we wish upon others that we care for or love.
Celebrate today by doing more than wishing someone is happy. Do something to make others happy. Send a happy and encouraging comments to each other. Some ideas include a phone call, making positive compliments, or cooking a special meal. Be creative. There are endless ways to make others happy.
I can't find where and when was this originated. Most likely it was created by a stationary or Ecard company, a candy company, or other gift giving venue. Check HolidayInsight.com for details.