Physical Danger
Broken bones, bloody noses, chipped teeth, and head and neck injuries are common for this sport, so keep in mind how much your parents paid for orthodontia.
One of the biggest dangers on the pitch are the concussions, which are as commonplace in rugby as fleabites and kitty litter are to your friendly neighborhood cat lady (source). Nobody wears helmets (much less shoulder pads or shin guards). Oh, and a scrum is basically nine guys pushing their heads into nine other guys.
Even a boxer looks at you like you're taking way too many chances.
Many health professionals warn that rugby's just too dangerous for either kids or adults to play. There are about forty injuries per 1,000 playing hours, which is pretty much comparable to football—but overall, both football and soccer rank safer than rugby when you're talking neck, back, and other critical injuries (source).
This is definitely a highly dangerous game, no matter how you knock it—or more accurately, how it knocks you.