I could just say it's because I'm a South African, but to be honest I wasn't that into rugby as a little kid, I was part of my grade school rugby team but didn't really want to play (and after grade school never did again unfortunately

went on to play hockey in high school), but during gradeschool at around the age of 8 or so I was so hooked on watching rugby, it's just the most awesome game in the world to view as a spectator.
some of my fondest memories are waking up at 4 in the morning with my dad to watch some Super 12 games or internationals.
But about 5 years ago I really wanted to start playing the game again, and eventually last year I dragged myself to some touchies games with a buddy of mine, first game felt like I was going to puke all the time, next game I played for a good hour, next game it got even better.
Like so many people mentioned already, it's the only game in the world I can think of that's still as honest a sport as you can get, people bash the **** out of each other one minute and act like brothers in arms the next, and most of all you know that most of the players out there are playing the game because they really honestly love it to death.