I once had an experience with an employee that got me thinking about the power of charisma and likability. 

This guy was awesome. He was a blast. He was energetic and articulate, and whenever we crossed paths I walked away feeling that I'd just interacted with a uniquely compelling soul. Eventually, he accepted an offer elsewhere. I chatted with some of his teammates afterward, and most of them struggled to pinpoint his contributions to the company. 

He'd been in all the meetings, he'd made his presence felt, but his actual achievements were hard to define. I doubt it was intentional, but he'd gotten away with doing nothing simply because he had a great personality.

Why we're blinded by crowd-pleasers. 

Engaging, popular employees are able to float by for two basic reasons. The first is that they're fun to have around. Work can be soul-crushing even on a good day, and colleagues who keep us laughing and excited are viewed as a precious resource. 

Secondly, most of us learned at a young age to equate popularity with success. The kid at school who kept his head down and got good grades was invisible; the kid who attracted swarms of friends was admired and envied.

This bias lasts well into adulthood. Popular but unproductive employees escape scrutiny for a long time because the fact that people find them likable creates an illusion that they're killing it. 

The habit of equating popularity with success is something you have to consciously train yourself out of. It'll keep charismatic types from wasting your company's time and money, but there's another benefit that's just as important. 

Why first impressions can be highly deceptive. 

Wowing someone in an interview is a talent. It's similar to acting--the person sitting across from you knocking your socks off with their eloquence and wit is putting on a show. 

Even intense awkwardness or nervousness during an interview is no indication of how someone will perform as an employee. The only thing it tells you is that they're bad at interviewing. 

Expecting to be wowed by an interviewee--expecting them to act like the cool kid at school--can lead you to miss out on great hires. I've adopted two strategies to help overwhelmed interviewees calm down and give me a better sense of who they really are:

1. Be open.

If you see that a candidate is sweating, fumbling for words, or behaving like a deer in the headlights, openly acknowledge it.

Tell them, "Look, I can sense you're feeling a little on edge. Rest assured that there are no right or wrong answers here. I get nervous, too--I might even be more nervous than you are. So don't feel weird."

Nine times out of 10, reassuring someone that you understand why they're nervous and that it isn't making a bad impression will have an immediate and positive effect. 

2. Go for a walk.

If that fails, ask your sweaty candidate to take a walk with you around the office. Offer them a soda or snack, as you're feeling like one yourself.

Walk side by side through the halls. They're no longer under your scrutiny; they're just having a stroll with you and engaging in conversation. By the time you return to the interview room and are once more seated across from each other, it'll feel more like a friendly chat than an interrogation. 

Why even great employees can lose their effectiveness. 

Some people seem born to work for startups. They just have a style that almost reflects the idea of a startup itself--cool, experimental, always thinking outside the box, impatient with conformity, etc.

Unfortunately, employees who work wonders at getting a startup up and running can lose their effectiveness as the company grows. They stop contributing meaningfully, but their likability and history with the company keeps it from being obvious. 

Be considerate to these people. They pitched in at a difficult time and assisted in transforming you from a wannabe into a real competitor. Recognize that hanging onto them for sentimental reasons does more harm than good to both parties, and use all your influence to help them find a place where they can shine again.

As you conduct performance reviews and consider promotions, remember the difference between being loved and respected. You love a person for who they are; you respect them for what they do. 

Confusing popularity with efficiency is a great way to slow your company's progress. Promote the people you respect the most; the ones who prove their worth by keeping their heads down and getting good grades, rather than attracting swarms of admirers.