Why Diwali is called as festival of happiness?

Answer 1

Diwali is called Festival of Happiness because the 6th Guru Hargobind Singh Ji was returned peacefully back home.

Also Deepavali or Diwali is a festival where people from all age groups participate. They give expression to their happiness by lighting earthen 'diyas' (lamps), decorating the houses, bursting firecrackers and inviting near and dear ones to their households for partaking in a sumptuous feast.

The lighting of lamps is a way of paying obeisance to god for attainment of health, wealth, knowledge, peace, valor and fame.

It is one time in the whole year that children volunteer to leave their beds long before the day begins. In fact, the traditional oil bath at 3 a.m, is the only chore that stands between them and the pre-dawn adventures. They emerge, scrubbed clean to get into their festive attire, and light up little oil lamps, candles and scented sticks (agarbathis), the wherewithal for setting alight crackers and sparklers.