This is our one and only chance at mortal life—here and now. The longer we live, the greater is our realization that it is brief. Opportunities come, and then they are gone. I believe that among the greatest lessons we are to learn in this short sojourn upon the earth are lessons that help us distinguish between what is important and what is not. I plead with you not to let those most important things pass you by as you plan for that illusive and nonexistent future when you will have time to do all that you want to do. Instead, find joy in the journey—now.
President Thomas S. Monson, "Finding Joy in the Journey", General Conference, October 2008

Many times on this journey through mortal life, I just want sit down on the side of the road and rest. Just relax for a bit. This journey takes a lot out of me. Whether spiritually, mentally or even physically. Sometimes, all facets together.
I believe that those are moments when joy is the greatest...or can be if I just keep moving. When life is the most grueling, joy and happiness is the most abundant. Or it can be, if we look for happiness in the right place. In that place we will find joy.
And afterall, we exist to find that joy (2 Ne 2:25). Every moment of our lives. Joy isn't a myth. Joy is not found only at the end of a long journey. Joy is attainable....now. Joy exists. But we have to be walking this journey alongside the Master of joy. We have to be yoked with Someone who is always happy, always positive, always smiling, always tender. Even if we fall and take the yoke with us. He patiently and lovingly waits for us to ask for help to get back up.
We won't ever get another chance at this life. Seek for happiness and joy now. If frustration muddles its way into life or if an obstacle suddenly appears on the path, focus more intentionally on Christ and His gospel. He will help us through it or over it.