Not everyone who creeps you out is harmful. But if you see any of these indicators in someone, realize that they may be untrustworthy and take time to examine who they are, even if you care about them.
A major red flag. Stand too near, refuse to take no for an answer, or tickling after you beg to stop are indicators to pick on.
It's possible that some individuals are simply incapable of understanding the meaning of a hint, but it's also possible that dangerous people are doing these things in order to test you or to see how far they can go in pushing you beyond your limitations.
Sociopaths and narcissists stare fiercely. They will stare intently at their goal. This is another way they test limits. They may say or do something uncomfortable before or after their look to test you.
Although some individuals enjoy talking, manipulators aim to dominate every discussion. They also breach auditory space and other paralanguage indicators of control. They may be charming and good storytellers, but they're hazardous.
Narcissists become agitated when things don't go their way. Their moods will be severe in social situations. They may modify themselves and change their nonverbal behaviors instantly. It may be so manipulative that you may not recognize it until the individual has pulled you in.
If someone you recently met starts disclosing themselves, they may be unstable or untrustworthy. This demonstrates loose limits that can spiral out of control.
If your new relationship is moving quickly, it may be beneficial. However, dangerous people may rush in to build false trust. Step back if it feels too fast—you may be in danger.