We should live happily because once the body is dead and is reduced to ashes; it can never come back to life.
One must enjoy life to the core. What is enjoyment? It is to eat delicious food, seeking the company of the beautiful and young, wearing good clothes and accessories, decorating oneself and experiencing instant gratification wherever possible. Indian tradition takes a holistic view of human nature. It argues that material aspects, may be for human existence, do not exhaust the whole of the personality of a human being. It recognizes that besides having physical needs and cravings, we have spiritual aspirations also. Why limit human aspiration to only the physical plane?
The spiritual goal alone differentiate the human being from other forms of life. A man does not aspire for just artha and kama or the economic and the emotional; he also wishes for dharma and moksha , the moral and the spiritual. So it’s not as though we only seek the ephemeral and fleeting, we are inclined also to look for what could be eternal and enduring.