Answer:
LOVE!
When you love someone, that person makes you truly happy and spending time with him or her uplifts you in ways you may not have felt possible. Often, when you are with the one you love, even the worst situation can seem like fun. True love brings happiness and fills your life with joy. And if that love fades or if the love of both person breaks it leads to a painful experience that can lead you to have life-lessons and reflections.