(Author’s note: Quite a few readers contacted me after this column was published. You made some really good points, and I listened. So, I wrote a sequel: 17 Simple Habits That Make You Look More Professional.)

Picture this. I was at a networking event last winter. It was cold outside, but quite warm in the room. Most of us balanced winter coats and heavy bags. I was making small talk with a few people when a new guy approached the group.

“Damn, you guys are carrying a ton of s–t,” he said. “You know, you can check your
s–t for free at the coat check.”

Boom! Instant credibility suck. I get that he was trying to help us, but none of us paid him any mind after that introduction.

It’s not really just that the guy swore; most of us are pretty immune to that these days. It’s that three of his first 22 words were curses (assuming you count “damn” as a curse). That’s just lazy, as if he couldn’t be bothered to come up with better descriptions of all the things we were carrying. Instead, he went with the barnyard default, and that made him seem unserious and unprofessional.

(Just off the top of my head, since I’m sure some of you are about to ask what he could have called the things we carried instead: coats, bags, laptops, stuff, purses, briefcases, jackets, coats, gear, kit, pouches, totes, baggage, portage, luggage, junk, tunics -- hey, call my a bag a man purse, if you want to at least score a C-minus joke).

The truth is, nobody’s perfect. We’re all prone to semiconscious verbal foul-ups that make us look less than impressive. That’s why we all need a reminder now and then. Here are 10 examples of unprofessional behavior to avoid.

1. Lazy profanity.

OK, this one really is at the top of the list. Again, it’s not the profanity itself (although that often doesn’t help). It’s the laziness. If someone uses the F-word as an all-purpose adjective, it makes you wonder whether they’re equally uncreative and slothful in everything they do.

2. Lateness.

I admit this is a tendency I’ve had to work hard to combat in my own life. The phrase “Murphy Standard Time” would not be met with blank stares by some of my friends and family. Yet I’ve learned that being on time is a matter of respect. Show up when you say you will, and you send a message that you’re professional enough to care.

3. Leering.

We’re all human. We’re mammals. We notice alluring members of whatever gender we’re biologically predisposed to be attracted to. Yet that same humanity also means we should have the self-control to keep the “up-and-down look” under control, so to speak. Eyes up here, my friend, or you’ll look like a creepy amateur.

4. Pollyannaishness.

I’ve always been bothered by the fact that the word “Pollyannaish” implies having too much unrealistic optimism. Check out the 1913 book if you don’t understand why. Still, when, after a disaster, a colleague or vendor insists things are absolutely fine while common sense tells you they’re not, it undermines their professionalism.

5. Flightiness.

To be flighty is to be fickle and irresponsible. Tell someone you’ll be at a certain place, or that you’ll accomplish a certain thing-and then never do it? Sorry, you’re flighty.

6. Disorganization.

(Anyone who gets more than 1,000 emails a day probably falls into this category.) As most of us who run businesses understand, clients and customers expect you to reply quickly. They want you to be able to talk about their situations (seemingly) off-the-cuff. If you aren’t in control of your own situation, they’ll wonder how you can possibly be in control of theirs.

7. Inarticulateness.

This one is so like, obvious, and yet a lot of people like, they don’t really get it. And that just, like, totally makes them seem like, not really professional, because they, like, can’t even get to the point of what they want to say and like, make it clear and stuff.

‘Nuff said. I’d actually throw bad grammar into this category as well, although with the caveat that we’ve all known some very smart, professional people whose language simply betrayed their lack of formal education, or whose first tongue wasn’t ours. (Seriously, if this column were written in French or Spanish, we’d all have a good laugh at my grammar.)

8. Secrecy.

Sure, we all have private lives, but most of the time our businesses don’t truly involve them. If you’re hiding important information from employees or clients, you’re not doing much for your reputation as a leader, and you’re probably making them wonder whether they can trust you.

9. Overpromising.

A really brilliant salesperson once told me her art of selling was about “making the maximum promise you can, consistent with your ability to deliver.” Entrepreneurs often push the envelope on this, but the key is to make sure you’re confident you will eventually be able to make good on your promises.

10. Cheating and lying.

These two are obvious. As President George W. Bush once tried to say, “Fool me once, shame on you. Fool me twice, shame on me.”