Joy and sorrow come and go like seasons. You cannot stop their flow, just like you can't stop the flow of seasons. What is needed is that we adjust to the visitor that is with us at the moment - whether it is joy or sorrow, pleasure or pain, shadow or light, sunshine or rain. All these shades of existence help us grow. They are finite parts of the Infinite picture. You cannot delete any of them. Instead of trying to embrace one shade and shun the other, you should try to rise above them and treat them all with equanimity.
Of course, this is not easy. This task needs practice, untiring practice, devotion and patience, the mother of all virtues. This is the path Lord Krishna talks about in the Gita. This is path all the religions of the world tell man to follow. In fact, there is no escape from this path. The various blows and caresses which we receive from this world, from Mother Nature and Father God, take us to the position where we see everything with an equal eye. The world is a school and God is the teacher. Ultimately, we will pass the test of the world and qualify for eternal Life, the Life beyond. Nobody will fail. The Lord is a beautiful teacher.
Hindu scriptures say: Atithi devo bhavah. Or, our guests are our Gods. Yes, they are our Gods. This is ancient wisdom, the distillation of centuries of observation. It is a way of life with us, something those alien to our culture won't understand easily. But we have lived this thought, welcoming diverse cultures with open minds and arms and helping them intermingle with our own ethos.
Atithi devo bhavah has to be lived not only on the level of physical guests, like the British, the Greek or the Muslims, but also on the metaphysical level: the divine visitors of joy, sorrow, pleasure, pain, fitness, ill health, etc. All these visitors to our realm should be greeted with the same grace and courtesy.