So basic, so simple. But it was (and still is) so hard for me to do.   I am shy, an introvert…INTJs unite!  I would get embarrassed saying hello to people I didn’t know. It just got easier to look at the ground and walk by.   Except it’s not polite. It’s not nice.  People interpret the absence of saying hi to mean something else: you’re not important, I don’t care about you, I have other things to do, I’m annoyed about something you did or didn’t do.  Nature abhors a vacuum.   So when you are at work, say hi. And smile.