There are some people out there who have an occasional lapse in a sense. They're the kind of people who you see driving into Looney Tunes-Esque drawn on tunnels (yes, there's genuinely one of those in here), or the sorts of people who really can't tell their "you're" from their "your".
Odds are you have met someone lacking in the sensitive area, or maybe you've been that person yourself from time to time. Either way, I'm certain you'll enjoy these 16+ people who never cease to amaze me with their stupidity.