If you’ve ever asked for a raise, bargained for your dream assignment, or even just negotiated for the cubicle with a better view, you’ve likely asked yourself how to be appropriately assertive—not too cocky, but not too meek.

“No one would disagree that if you push too hard you’ll start to strain your relationships, and if you don’t push hard enough you’re not going to get the resources you need,” says Daniel Ames, a professor of management at Columbia Business School. “This is one of the most common challenges professionals and leaders struggle with.”

Not only is it common, but it’s complicated to overcome: In a series of four studies in the journal Personality and Social Psychology Bulletin, Ames and Abbie Wazlawek, a management doctoral student, found that people are pretty lousy at assessing how others view their assertiveness. Specifically, the researchers found that the majority of people who are viewed as too timid consider themselves just assertive enough, if not overly assertive. On the other hand, people who come off as too pushy often think they are appropriately assertive or not assertive enough. The results were similar among both men and women.

“People who are getting it wrong often think they’re doing it right,” Ames says.

Most surprisingly, though, the team also found that the opposite is true: People who are getting it right often think they’re doing it wrong. That is, many people who others rate as star asserters fear that they’re too forceful. “It’s all in the direction of people thinking, ‘I’m coming across as a jerk, I’m coming across as a monster,’” Ames says. “That puzzled us.”

Why are we so bad at knowing how we’re perceived? For one, it’s human nature to think highly of ourselves: From attractiveness to intelligence, most of us think we’re above average. (Reality check: That’s statistically impossible.) Still, it helps explain why people who come off as over- or under-assertive are likely to think they’re doing just fine.

But it doesn’t explain why many star negotiators don’t realize they’ve nailed it. For this bunch, the blind spot may be in part attributable to other people’s reactions—not a lack of self-awareness, Ames and Wazlawek found. For instance, if your boss gasps, staggers, and says, “Are you kidding?” when you ask for a week off to care for a sick parent, you’re more likely to think your request has crossed the line. “They’re putting on an act, but you feel like that’s a judgement on your character,” Ames says.

So what does all this mean for your next big (or little) negotiation? First, take your assertiveness skills seriously, Ames says. “It’s a real professional limiter if you’re reliably seen as pushing too hard or not hard enough.”

Next, try to get feedback before you negotiate since it’s tough to gauge where you fall on the assertiveness spectrum in the heat of the moment. Look to anonymous evaluations from colleagues above and below you (a.k.a. “360 evaluations”), or ask a trusted mentor or colleague about your assertiveness strengths and weaknesses. Even better, practice your pitch with a professional pal and ask for feedback. “That can help you get a step closer to insight,” Ames says.

Finally, keep in mind that it’s pretty common for people on the other end of the bargain to overreact. “If someone seems exasperated, you can try to parse their reaction,” Ames says. “If you probe a little, you might find that there’s nothing there.”

Photo of person putting fist down courtesy of Shutterstock.