Stress
Like any other sport, those megafans who actually follow rugby take it very seriously. It can be similar to soccer, as the games typically grow to the national level. Thanks to events like the Rugby World Cup and the Olympics, you'll have the stress of the nation's pride and honor weighing on your shoulders. No big deal.
Not only that, but this is a pretty dangerous sport. Worrying about injuries can be pretty stressful as well. Especially considering—and we can't stress this enough—you aren't receiving any health care. It's not great to have to miss work because you broke both of your hands on a bad dive for the ball.
We'd also recommend that you don't tell the bosses that do provide you health care; they won't like hearing that their premiums are almost definitely going to go up.