When you think of this life, you'd realize there are so many moments of joy, times when you've laughed over something silly, felt excited over the prospect of something new, woke up smiling because you look forward to the day ahead. It helps to remember the goodness in this life, so we are not drowned out by the bad days. Remember so deeply the joy and the goodness in your life, that it is planted into your soul, that you do not have to remember the particular incident to access the joy.
Let us remember what (or who) once brought us happiness, and let us give gratitude to that situation (or person). Even if it no longer is, it once gave us joy, and the memory of it can continue to give us joy. May we cherish that moment, that experience, that good in our lives. However briefly we held this gift in our hands, there was good in it, and by remembering it, we are keeping that goodness alive.