Want to make your commute a little bit better? You're going to interact with many people on your way to or from work. Next time one of them does something for you, say "Thank you."
Someone held the door open instead of letting it hit you in the face? "Thank you."
Oncoming car stopped at a green light so you could cross the street? "Thank you."
Girl that gives you your coffee and bagel in the morning? "Thank you."
Get the idea? It's not that hard. My 2 year old can do it. It only takes a second to make somebody else's morning. And who knows, one morning you might find that people are saying it to you, too.