The go-first principle

Most people are kind and ready for kindness. They just need a nudge.
Be first to say hello to the cashier.  When you meet eyes with a stranger, be first to give them a sincere smile.   Introduce yourself to someone you see often but haven’t formally met.

Yes, not every human is welcoming.  But this principle pays dividends and you’ll find you have very little to lose, even in the worst of cases.

(Hat tip: Gabby Reece)

Confidence and Arrogance

Confident people believe in and act on their own value and importance.

Arrogant people have an inflated and unhealthy attachment to their own importance.  While they sometimes appear to be confident people, they are often just overcompensating to mask their insecurities.

Here’s what distinguishes one from the other:
Arrogant people seek constant validation that they are “better”.
Confident people look to increase confidence in others.

You teach people how to treat you

In every interaction, you teach others how to treat you with your actions and words – or lack thereof.  It’s okay to have boundaries and it’s okay to assert them.  Those who matter will care and respect them.  Those who don’t care or respect them don’t matter anyways.

The point is that you are accountable, and that it is you who teaches others what’s acceptable.