You can’t build a strong professional network if you don’t open up to your colleagues; but doing so is tricky, because revealing the wrong things can have a devastating effect on your career.

Sharing the right aspects of yourself in the right ways is an art form. Disclosures that feel like relationship builders in the moment can wind up as obvious no-nos with hindsight.

The trick is to catch yourself before you cross that line, because once you share something, there is no going back.

TalentSmart has tested more than a million people and found that the upper echelons of top performance are filled with people who are high in emotional intelligence (90% of top performers, to be exact). Emotionally intelligent people are adept at reading others, and this shows them what they should and shouldn’t reveal about themselves at work.

The following list contains the 12 most common things people reveal that send their careers careening in the wrong direction.

1. That They Hate Their Job

The last thing anyone wants to hear at work is someone complaining about how much they hate their job. Doing so labels you as a negative person, who is not a team player. This brings down the morale of the group. Bosses are quick to catch on to naysayers who drag down morale, and they know that there are always enthusiastic replacements waiting just around the corner.

2. That They Think Someone Is Incompetent

There will always be incompetent people in any workplace, and chances are that everyone knows who they are. If you don’t have the power to help them improve or to fire them, then you have nothing to gain by broadcasting their ineptitude. Announcing your colleague’s incompetence comes across as an insecure attempt to make you look better. Your callousness will inevitably come back to haunt you in the form of your coworkers’ negative opinions of you.

3. How Much Money They Make

Your parents may love to hear all about how much you’re pulling in each month, but in the workplace, this only breeds negativity. It’s impossible to allocate salaries with perfect fairness, and revealing yours gives your coworkers a direct measure of comparison. As soon as everyone knows how much you make, everything you do at work is considered against your income. It’s tempting to swap salary figures with a buddy out of curiosity, but the moment you do, you’ll never see each other the same way again.