Jack is a contract worker in one of my companies. Not a day has gone by in the last three months where I haven’t heard him complain.

Jack is tall, muscular with a deep voice and almost shocking good looks a la George Clooney. Jack’s a personal trainer. We’re out in sunny Southern California, in a brand new facility with among other amenities, a staff lounge, full kitchen, wifi, a conference room and really deluxe locker rooms. We even have the most elusive thing in Los Angeles: free parking.

It’s such a nice place that The New Girl filmed here as did Yahoo Sports. And PopSugar is about to do a segment here for their website.

However, nothing seems to please Jack. He complains in front of clients. He complains in front of other staff. He complains to me when he walks into my office and interrupts my work.

His complaints are unnerving because they are so counterintuitive.

For example, we bought another expensive treatment table, so staff wouldn’t have to share the one we already had, or stretch clients on floor mats. On the first day, Jack let me know that he hates where we put this table. He did this by yelling through my window, in front of a dear client.

Jack also reported that he doesn’t like the new, sleek water dispenser, because the water bottles don’t have handles. I don’t understand this either, I’m just reporting.

Jack is infuriated when there’s just regular bathtowels in the locker room. He went into my creative director’s office and announced: “Ladies! There are no giant bath towels on the shelf. Take care of this.” My creative director has nothing to do with towels. Our ad agency just shares part of the building.

When he’s not complaining, I adore Jack. He’s got a big heart and a surprising sunny side. Plus, he knows the entire score to The Music Man, so he and I can break out into song when we hear the letter “p.” You know, “P, which rhymes with T and that stands for Trouble, right here in river city.”

My concern is for my companies and the staff that share the building. One incessant complainer can kill the productivity and good vibe of an entire organization. Why?

Because like a cold, complaining is contagious. But worse, it’s a sickness that gets bigger and bigger as it’s caught among the staff. According to Dr. Robin Kowalski, a professor of psychology at Clemson University in South Carolina, the act of complaining kicks off a one-upsmanship among co-workers. We’ll name them A, B and C.

A: “Can you believe it? I have to work this weekend!”

B: “Oh yeah? I had to put in 10 hours of overtime last week.”

C: “Well, I have to file this report by the end of the day and I haven’t even started it!”

That’s right. What goes around becomes an increasingly nastier litany of grousing. Why? Because complaining is a form of bonding. Shock to me! Dr. Kowalski says complaining helps break the ice, start conversations and otherwise become the basis of relationships. A maladaptive bond, but a bond nonetheless.

The New York Times reporter Phyllis Korkki notes incessant complainers are at a “high risk of being fired.” Plus, they are ruining their reputations with each miserable syllable falling from their mouths.

Is complaining casting a shadow on your personal brand? Think, before you let out the next grumble.

After all, by now you’ve learned to stifle a coughing fit in the crook of your arm, so you don’t spread germs. Figure out where to put your moans and groans. You’ll be saving your personal brand, your job and maybe the income of co-workers you’d be contaminating.