21 unprofessional habits that could cost you your job

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Annoying your coworkers, while never a good idea, is one thing. But annoying your boss with your unprofessional habits could cost you your job.

To help you avoid letting your bad habits get the best of you, we asked experts to highlight some of the least professional behaviors you could demonstrate at work that will put your job on the line or cost you a promotion.

Here are 21 things you could be doing all wrong that may make your boss think you're not right for the job:

Showing up late to work

"Punctuality is critical," Rosalinda Oropeza Randall, an etiquette and civility expert and the author of "Don't Burp in the Boardroom," tells Business Insider.

"The professional thing to do is to arrive on time, ready to do what is expected. It's not like they just sprung this job on you," she says.

Rolling in 10 minutes late to every meeting

Similarly, showing up late to meetings shows that you neither respect your coworkers — who showed up on time, by the way — nor the meeting organizer, Vicky Oliver, author of "301 Smart Answers to Tough Interview Questions" and "Bad Bosses, Crazy Coworkers & Other Office Idiots," tells Business Insider.

"Keeping people waiting can be construed as inconsiderate, rude, or arrogant," Randall says.

Being negative all the time

Repeatedly responding to suggestions with a pessimistic or contrary attitude can be construed as being uncooperative, Randall says. Phrases like "That won’t work," "That sounds too hard," or, "I wouldn’t know how to start," should be avoided.

Similarly, complaining too much puts you in a bad light.

"While there may be times when everyone feels the desire to complain about the boss, a coworker, or a task, voicing it will only make you look unprofessional," Randall says. "It's even worse if you complain every day, all day, from the moment you walk into work. Before long, people will go out of their way to avoid you."

"There's nothing as energy-draining as having to deal with a pessimistic coworker," Rosemary Haefner, chief human-resources officer for CareerBuilder, tells Business Insider. "Things do go wrong, but even when they do, focus your energy towards what you've learned from a bad situation."

She points to a recent CareerBuilder survey, which shows that a majority of employers — 62% — say they are less likely to promote employees who have a negative or pessimistic attitude.