It starts with an uneasy feeling: You’re left out of meetings you used to attend. The boss stops offering suggestions. Once-friendly colleagues turn cool.

How can you be the last one to know you’re failing or flailing at work?

“I never saw it coming,” says Nancy Halpern of a layoff on a previous job years ago as a division head for a retailer. “I thought I did a great job. I ran a department and had achieved great results. I prided myself on being very dedicated and committed,” she says.

She sometimes had disagreements with her boss, and her boss occasionally canceled meetings with her, Ms. Halpern says. But she didn’t respect her supervisor enough to try to forge a closer bond.

She realized too late that her boss placed a high value on loyalty and saw her behavior as insubordination. She should have asked her for frequent, specific feedback, such as, “What should I do less of? What should I do more of?” says Ms. Halpern, principal of KNH Associates, a New York leadership-development consulting firm. And she might have taken a few cues from peers her boss favored and picked up on strategies they used.

Misreading important external factors on the job, such as your boss’s values or priorities, is a common misstep. “When your manager starts ignoring you, there’s a reason for it,” says Elaine Varelas, managing partner of Keystone Partners, a Boston career-management consultant.

Scott Samuels sensed trouble when his supervisor stopped giving him feedback during a previous job as a general manager of a new outlet for a food retailer. He also found himself left out of important meetings. He later realized he hadn’t understood exactly how his performance would be evaluated.

He says he was striving to build revenue and keep customers and employees satisfied. But senior managers were intent on posting short-term profits, and “in order to move up and get promoted, one of your primary roles was to make your boss look good. It was sort of a shocking experience,” says Mr. Samuels, founder and chief executive of Horizon Hospitality Associates, an Overland Park, Kan., executive-placement firm.

He soon quit to start his own company, where he makes a point of explaining his own yardsticks of success to new recruits. “I have a tendency to want to scare people off initially. I want them to have a reality check on the pros and cons” of the job, he says.

Other employees spin blindly off-course by misjudging their own skills. One of the most common blind spots is “an overinflated sense of your strengths and capabilities,” says Kevin Cashman, Minneapolis-based author of “Leadership From the Inside Out” and global head of Korn Ferry’s CEO development practice. “The second is a lack of awareness of your [personal] vulnerabilities.”

One common distortion is called top-down thinking: People who have a preconceived belief about their skills, such as thinking they’re good at logical reasoning, tend to assume they’re performing well at any task that requires logical reasoning, research shows.

Also, in a pattern called the Dunning-Kruger effect, people who are poor performers in a specific domain also lack the ability to recognize that they’re performing poorly in that arena.

And they resist efforts by others to clue them in. People who lack emotional intelligence, for example, tend to disparage negative feedback, saying it’s either inaccurate or irrelevant, according to a 2014 study in the Journal of Applied Psychology.

Strengths of even supposed superstars can blind them to their weaknesses and leave them on thin ice. People who are very good at core job skills, such as sales or accounting, often believe those capabilities give them such a powerful advantage that getting along with others doesn’t matter, says Ralph Roberto, president of Keystone Partners. The boss may tolerate the problems these egotists cause by clashing with supervisors, colleagues, subordinates or clients—until they become more trouble than they’re worth. Then the boss delivers a shocking message: “I don’t care how good you are. You’re gone,” Mr. Roberto says.

Bosses are often slow to criticize employees who are struggling. “Some people send a subtle signal: ‘I don’t want negative feedback,’ ” Mr. Roberto says. “And managers dread delivering it, because they know it’s going to be a big fight.”

People often rationalize their failings by benchmarking their job performance against mediocre peers, rather than stars, saying, “I’m not that bad. Look at Joey over there,” says Brian Binke, president of the Birmingham Group, a Berkley, Mich., affiliate of the Sanford Rose Associates executive-search network.

And peers are often the first to see the writing on the wall, he says. Like many managers, Mr. Binke has hesitated to fire poor performers in the past, worrying that it would upset other employees. But when he finally pulls the trigger, Mr. Binke says, the reaction from peers is often, “What took you so long?”

The risk of becoming isolated and unaware of one’s own failings increases as executives rise in the ranks into more complex jobs—especially if they surround themselves with friends and supporters who won’t find fault.

In a perilous twist, what were once your strengths can become weaknesses. Korn Ferry’s Mr. Cashman coached a food-company executive who prided himself on controlling all the details of businesses he ran. This worked fine until he was promoted to managing a unit so big that he couldn’t possibly keep a finger in every pie. “His need for control was squeezing the life out of his highest-potential people,” Mr. Cashman says.

The executive insisted that if he gave up control, everything would fall apart. No, Mr. Cashman says he told him: “Because you’re controlling, everything is falling apart.” The executive heeded the advice, learned to collaborate with subordinates rather than controlling them, and continues to advance in his career, Mr. Cashman says.

Signs You Might Be in Trouble Your boss stops dropping by your desk with suggestions.

You’re left out of important meetings you used to attend.

Once-friendly colleagues start to avoid you.

You never get any feedback.

You never ask for any feedback.

You start comparing yourself to mediocre peers rather than stars.

You’re not sure what your boss cares about.

You don’t care what your boss cares about.

More From Work & Family Work & Family Mailbox: Sue Shellenbarger Answers Readers’ Questions

Write to Sue Shellenbarger at sue.shellenbarger@wsj.com