Oh, sure, it’s easy to hit “unfollow” on Twitter, but for some reason, pulling the plug on Facebook friends is more difficult — perhaps because the terminology of “unfriending” actually forces you to admit that your relationship with that junior-high volleyball buddy is over. With that in mind, it’s illuminating to learn what drives people to unfriend: over 55 percent of respondents to a new Nielsen survey will boot an acquaintance who makes offensive comments, while 41 percent will dismiss someone they just don’t know well (which raises the question of why they accepted the person’s friend request in the first place). Meanwhile, Nielsen also learned that the single most important factor in adding a friend is knowing them in real life — which may seem obvious, but does give us a little bit of hope that social media isn’t entirely exploding the boundary between real-world friendships and virtual ones. See the entire infographic and learn more about the study at Nielsen. [via Gawker]