Indians have a very unique relationship with festivals – regardless of religion. A Catholic would enjoy a fat traditional Hindu Wedding just as much as a Hindu would enjoy Iftar at a Muslim's house. It's not the scale of celebration that brings everyone together, it's more like the fact that we get to celebrate a happy occasion with the people we love.
Eid in MumbaiThe Sun
Rather than material things, it's the emotional factor that sparks up an Indian festival. The happiness on a person's face, the tears of joy, the laughter of children, and so on. Each Indian celebration is well known for its own uniqueness. To prove my point, try to attend any Indian wedding/festival. The different ceremonies, the rush, the FOOD, the fancy clothes, the music, and the dancing. If that doesn't fill your body with emotions, nothing will.
Traditional Indian WeddingManhattan Brides
Also, when an Indian family celebrates a festival or a special occasion, it includes a LOT of people. For a country of more than a BILLION people, you can only imagine how many people are invited. Your dad, your uncle, your uncle's brother-in-law, your uncle's brother-in-law's father. If you can make up a relative, the chances of that relative being invited are quite likely.
But it's like I said, Indian festivals focus more on the emotional values attached. The more the merrier is a standard motto for such festivals.