Do you open doors for people? Do you allow people in the grocery store with one item to go ahead of you? Do you give your seat to someone who needs it on a bus or let someone take the first cab?
Imagine what a different world we would be living in if we all practised a little more politeness & courtesy. If you want to have a different world.....BE THE EXAMPLE!
It's the kind thing to do. So, do it! You'll make someone feel special...in fact you'll feel better about yourself as well.