There are plenty of ways to turn people off.

In fact, most of them don't require much effort. All it takes is one look at your social media activity or a casual in-person introduction to make someone realise they just don't want to spend time with you.

We've rounded up some of the most common social turn-offs online and in person, as well as how to avoid them. Read on and see which ones you've been guilty of.

1. Sharing too many photos on Facebook

You might be eager to share snapshots of your honeymoon, cousin's graduation, and dog dressed in a Halloween costume, all within a 24-hour period.

But research has found that posting too many photos on Facebook can hurt your real-life relationships.

"This is because people, other than very close friends and relatives, don't seem to relate well to those who constantly share photos of themselves," lead study author David Houghton, PhD, said in a release.

Specifically, friends don't like it when you've got too many photos of family, and relatives don't like it when you've got too many photos of friends.

As Ben Marder, PhD, another author on the study, put it: "Be cautious when sharing and think how it will be perceived by all the others who may see it. Although sharing is a great way to better relationships, it can also damage them."

2. Having too many or too few Facebook friends

In one study, researchers asked college students to look at fictional Facebook profiles and decide how much they liked the profiles' owners. The study took place in 2008, and the students had about 300 friends each.

Results showed that the "sweet spot" for likability was about 300 friends. Likability ratings were lowest when a profile owner had only about 100 friends, and almost as low when they had more than 300 friends.

As for why 300-plus friends could be a turn-off, the study authors write, "Individuals with too many friends may appear to be focusing too much on Facebook, friending out of desperation rather than popularity."

On the other hand, the researchers acknowledge that if you look at a population where the most common number of Facebook friends is 1,000, the sweet spot for likability could be 1,000.

Keep in mind, though, that one survey found that the average number of Facebook friends among adult users was 338 in 2014.

Interestingly, the study also found that participants weren't consciously aware that they liked people less when they had too many or too few Facebook friends.

3. Disclosing something extremely personal early on in a relationship

In general, people like each other more after they've traded confidences. In fact, self-disclosure is one of the best ways to make friends as an adult.

But psychologists say that disclosing something too intimate — say, the fact that your sister is having an extramarital affair — while you're still getting to know someone can make you seem insecure and decrease your likability.

The key is to get personal without getting overly personal. As one study led by Susan Sprecher at Illinois State University suggests, simply sharing details about your hobbies and your favorite childhood memories can make you seem warmer and more likable.

4. Asking someone questions without talking about yourself at all

That same study by Susan Sprecher found an important caveat to the idea that self-disclosure predicts closeness: It has to be mutual. People generally like you less if you don’t reciprocate when they disclose something intimate.

In the study, unacquainted participants either engaged in back-and-forth self-disclosure or took turns self-disclosing for 12 minutes each while the other listened.

Results showed that participants in the back-and-forth group liked each other significantly more.

As the authors write, "Although shy or socially anxious people may ask questions of the other to detract attention from themselves, our research shows that this is not a good strategy for relationship initiation. Both participants in an interaction need to disclose to generate mutual closeness and liking."

5. Posting a close-up profile photo

If your LinkedIn profile features an image of your face practically smushed up against the camera, you'd be wise to change it.

Research suggests that faces photographed from just 45 centimeters — about 1.5 feet — away are considered less trustworthy, attractive, and competent than faces photographed from 135 centimeters, about 4.5 feet, away.

6. Hiding your emotions

Research suggests that letting your real feelings come through is a better strategy for getting people to like you than bottling it all up.

In one study, researchers videotaped people watching the fake-orgasm scene from the movie "When Harry Met Sally ..." and a sad scene from the movie "The Champ." In some cases, the actors were instructed to react naturally; in another they were instructed to suppress their emotions.

College students then watched the four versions of the videos. Researchers measured how much the students would be interested in befriending the people in the videos, as well as their assessments of the personalities of the people in the videos.

Results showed that suppressors were judged less likable — as well as less extroverted and agreeable — than people who emoted naturally.

It probably goes back to that idea of reciprocation. The researchers write: "People … do not pursue close relationships indiscriminately — they probably look for people who are likely to reciprocate their investments. So when perceivers detect that someone is hiding their emotions, they may interpret that as a disinterest in the things that emotional expression facilitates — closeness, social support, and interpersonal coordination."

7. Acting too nice

You might think you'll win people over by acting altruistic, but science suggests otherwise.

In a 2010 study, researchers at Washington State University gave college students points that they could keep or redeem for meal-service vouchers. Participants were told that they were playing in groups of five — even though four of them were manipulations by the researchers — and were told that giving up points would boost the group's chance of getting a monetary reward.

Some of the "fake" participants would give up lots of points and only take a few vouchers. As it turns out, most participants said they wouldn't want to work with their unselfish teammate again.

Some participants said the unselfish teammate made them look bad; others suspected they had ulterior motives.

The real-world implication here is that you don't want to be the coworker who always agrees to get pizza for the meeting or fix the printer when it's jammed. Instead, it's OK to say no sometimes, as long as you explain why you can't commit.

8. Humblebragging

To impress friends and potential employers, avoid complimenting yourself and trying to disguise it as self-criticism.

This behaviour, otherwise known as "humblebragging," could be a turn-off, according to a recent study.

In the study, college students were asked to write down how they'd answer a question about their biggest weakness in a job interview. Results showed that more than three-quarters of participants humblebragged, usually about being a perfectionist or working too hard.

Yet independent research assistants said they'd be more likely to hire the participants who were honest, and found them significantly more likable. Those students said things like, "I'm not always the best at staying organised" and "Sometimes I overreact to situations."

Another alternative is to talk about weaknesses that don't directly relate to the job — for example, a fear of public speaking if you're applying for a writing position.

9. Getting too nervous

Never let 'em see — or smell — you sweat. Research suggests that the odor of your nervous sweat may subconsciously influence people's judgments of your personality.

Back in 2013, researchers at the Monell Chemical Senses Center had participants watch videos of women in everyday situations, like working in an office and taking care of a child. While watching the videos, they sniffed three kinds of sweat in a row: sweat that someone had produced while exercising, sweat produced during a stressful situation, and sweat produced during a stressful situation that had been covered up with antiperspirant.

Participants were then asked to rate the women on how competent, confident, and trustworthy they seemed.

Results showed that participants rated the women lower on all measures when they smelled the stress-induced sweat. When they smelled the stress sweat that had been covered up with antiperspirant, they rated the women more positively.

Bottom line? If you're prone to nervous sweating, be liberal with the deodorant.

Read more: