When someone generally misunderstands social behavior as a whole as has an unnatural degree of innocence still left in them. These instances are categorized by naivety and general ignorance about the topic at hand. Also relates to: being overly optimistic about a situation or society as a whole.
Person 1: "Dude, I'm getting so hammered tonight."
Person 2: "That sounds like it would hurt..."
Person 1: "I can't believe you're pulling a Benji on me right now. You're not coming with us."
To do a Benji: To go off on your own while playing squads in Playerunknown's Battlegrounds, leaving your team alone, getting three knockouts then dying, making your impact useless and then raging at your teammates for not helping you from across the map.
I thought we were going to go Rozhok, but Luke decided to 'do a Benji' and drop military island instead...