Its Nz's national sport which they have played with a passion for over a century or more. I have been a passionate AB fan for many decades but I must admit the RWCs for the ABs is ONE thing they have not always been good at since 1987. Some 'cynics' will say that between 1991-2007 the ABs were good at choking or good at winning RWC's in Nz only What is often forgotten is that South Africa prior to their return to international rugby in 1992 were actually the most feared rugby side in the world despite their limited International competition in the 70s and 80s. The ABs had never beaten them in a test series in their own country despite over 50 years of trying (they finally won in 1996 ) while the Boks had beaten the ABs in Nz and had won the UK grand slam 4 times up to the 1960s predating the ABs first slam in 1978.

It's simply the sport-of-first choice in that nation. It's similar in the Pacific island nations, who are also strong in rugby despite their very small populations. The best example from another sport I can think of is Canada in ice hockey. Parents put ice skates on their kid's feet and sticks in their hands here as they can walk. Boys and girls. When you have players practising the necessary skills at such an early age, it's a tremendous advantage.

Rugby is like a religion in NZ and many kids want to grow up to be an All Black, plus, we know hoe to play the game.

Rugby is New Zealand's national sport. For example football is Spain's national,sport. All kids in New Zealand play rugby from birth.