The game itself is not that addicting - I tend to fall asleep after an hour or two, unless I'm online with my wife - but some people, it would seem, can become addicted to anything. Sex, food, pot (which, despite what you may have heard, has no physical dependency, only psychological), texting, pencil-and-paper role-playing games, Internet usage - if you're "that kind of person", you can become addicted.
Heck, I know one guy who gets jumpy and irritable if he has to go more than two days without a workout!
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Sodium is a metal that reacts explosively when exposed to water. Chlorine is a gas that'll kill you dead in moments. Together they make my fries taste good.