In case you haven't noticed, happiness is having a major moment. Cropping up all around us are very happy, catchy tunes, special DIY projects, major research projects and more, all in the name of happy. In my opinion, any theme with this much traction should be taken as a cue for marketers. In fact, happy birthday and anniversary messages are known to drive stronger than average engagement, and are often successfully used as opportunities to build loyalty and drive action. So let's get this party started and explore how to get happy in the inbox!