Truthfully, there is no better time to be happy than RIGHT NOW! Whatever is going on, however imperfect our world may be today, we need to develop the attitude and techniques to make the "present" appreciated for the gift that it truly is.
How do we do this, you ask? Great question! The first step is to acknowledge that life is a series of challenges. Someone with more of a negative slant may say that life is a series of problems. Either way, the point is that there is a tendency in one's mood to move towards anxiety and sadness: it is human nature to typically get stressed with change. Also we get stressed when we have to deal with situation after situation.
Recognition that we need to anticipate stress and a lowering of our moods as a natural part of life is itself the biggest lesson!
Think of it this way, we can't feel full all the time. Indeed, to feel satisfied we sometimes have to feel pangs of hunger. So too it is with happiness: sometimes we need to experience sadness in order to appreciate what it is to be truly happy!
Said differently, that "junk" drawer in your kitchen will likely get more messy than clean if nature is left to its own devices. We have to put energy into cleaning up that drawer in order for that drawer to be clean! So it is with happiness: we need to put the energy into our lives to keep happiness alive.
Don't make sadness the enemy. Accept what comes...but learn to control what you can to help yourself feel genuinely better!