What behavior has someone displayed that instantly caused you to write her or him off?

When in the middle of a conversation they flip through Instagram and twitter messages on their mobile device.

If they don't have the time to take a break from social media, than I don't have the time to wait for them to stop.

There is a member on here NASTY! That is putting it politely! I see some are quite enamored and make posts about how much they admire said user. Safe bet that we wont get along.

Creepy behavior towards children
Cruel, judgemental ,
On drugs / always drunk.
Thinking they are above others
Aloof and doesn’t pay any attention

Any display of undeserved superiority.

Mocking /unkind

bullying

When they were saying how their life is/was and you're supporting them,🧐then they add another account saying the opposite?! The person also made up b.s. about another user, not realizing I'd ask...[i][b]block![/b][/i]

Rudeness to “the help.”

Or someone leaving a mess in a conference room and saying someone will clean it up.

Once I realize they are sociopaths I’m done.

Yelling at a waitress or service worker

A non blood relative who has a toxic personality.