The Leadership Insider network is an online community where the most thoughtful and influential people in business contribute answers to timely questions about careers and leadership. Today’s answer to the question “What are the three most unprofessional things an employee can do on the job?” is by Shadan Deleveaux, co-founder of Technology For Families in Need.

In the not too distant past, the concept of professionalism was exhibited at work by wearing a navy blue or grey business suit, a crisp white shirt, simply styled hair and minimal, if any, jewelry. As the relaxed atmosphere of tech companies, and millennials’ preferences have pushed corporate cultures toward a more casual appearance, the line between what is and is not acceptable in the workplace can become blurred. Many business people have conflated the lack of a formal dress code with the lack of professional decorum. As a result, there is no shortage of unprofessional episodes that can take place. At one company I worked for, a summer intern apparently thought it was a career enhancing move to tell her HR contact that she was struggling through this particular day at work because of how ‘wasted’ she got the night before. She was wrong. Over the years there have been a multitude of improprieties committed at work, here are a few of the most common.

One of the most common unprofessional behaviors exhibited in the workplace is over-sharing. This particular area can be a fine line since it is ideal to be able to bring your ‘whole self’ to your place of employment. However, it’s important to realize that your employer is not your diary or your best friend. Prudence is always warranted. Talking about weekend plans is fine, but sharing the intimate details of a messy breakup or a divorce to a room full of acquaintances and relative strangers may not be the best use of company time.

See also: Shark Tank’s Robert Herjavec on the Most Unprofessional Thing an Employee Can Do

Dressing too casually
As I stated earlier, many companies have relaxed their dress codes to accommodate the desire for a more comfortable work environment. This is a huge win for employees, many of whom are logging long hours at the office. Feel free to dress down if your business environment permits it but it is important to understand that even when dressing down, your clothes should still be clean and meant for the office. In other words, under no circumstances (except for maybe Halloween) should you be wearing your pajamas to work. Lastly, if your coworkers can see your undergarments (or lack of), it is probably a good idea to rethink the outfit and put some more clothes on.

Chronic lateness
As workers days are filled with more and more meetings, tardiness will occasionally happen. That’s not an issue – the issue is chronic lateness. Whether it’s consistently arriving at the office long after your coworkers have been at their desks, or frequently arriving at meetings more than a couple of minutes after they are slated to start. Being chronically late not only shows a lack of regard for your teammates but it shows a lack of preparation on your part. It conveys the image that you are frazzled, not prepared, and scrambling. All of these things may leave others less than confident in your abilities. If climbing the corporate ladder at your company is important to you, you do not want to develop the reputation as being the ‘late-comer’. Prep beforehand and schedule a few minutes in between your meetings as travel time.

These three unprofessional behaviors should be avoided at all costs, but they are only a few examples on what is a very long list. If you have questions or a behavior that you’re not sure about, a good rule of thumb is to imagine your company’s CEO engaging in that behavior. If it would seem out of character for your CEO, then most likely you should avoid it too.