Asked about the challenges of being famous, Rowan Atkinson says the worst part is when people half-recognize you. Having gone through that experience once while getting spare parts for his Land Rover, Atkinson found it impossible to convince the fan that he was in fact the actor playing Mr. Bean.

“I bet you wish you were!” the guy said, and insisted Atkinson “try doing some look-alike work.” “You could make an absolute fortune!” The more Atkinson tried to prove who he was, however, the harder the fan held on to his conviction — to the point of getting angry with Atkinson for “going around the country, pretending to be Mr. Bean.”

Our brain’s ability to make quick, near-instant judgements is one of our greatest advantages as a species. Unfortunately, this skill is a two-edged sword, and when those judgements go wrong, the consequences can be disastrous.

The German word for a perfect look-alike is “Doppelgänger.” In a How I Met Your Mother episode of the same name, the gang finally meets the fifth and last body double they’ve been looking for, having collected a match for each of the five friends over the years.

Before they encounter Barney’s real look-alike, a fertility doctor named John Stangel, however, there are several false positives. Most notably, Lily excitedly points her friends to a pretzel vendor who, in fact, looks nothing like Barney. The catch? Marshall and Lily have agreed to try for a baby once they see Barney’s doppelgänger — and Lily’s insistence on having found him merely proves she is ready to have kids.

Humans have an amazing ability to see — literally and figuratively — but when we choose to see just what we want to see, we squander our potential. Sometimes, the consequences are harmless if embarrassing, as in the Mr. Bean case. At other times, our emotional investment into a point of view can have life-changing implications, like for Lily and Marshall.

Whether at work, in life, or with people: Most things are worth a second look. “Am I seeing the real thing? Or is this just a doppelgänger?” Ask before you judge, and even after you’ve made up your mind, always keep the door ajar.