It's often seen in New York City that people hold the door for the following person. It's a small gesture that lasts 1-2 seconds and ends with someone saying thank you.
Yesterday, I sat near the door in a long bus ride. This trivial gesture happened couple times. Somehow the altruistic kindness made my day. Momentary as it was, I still remember the warm feeling from seeing it happening.
Does it count if the door holder goes in first and holds it a little bit for the person after, or the gentlemanly thing of holding and extending the hand gesture, maybe with a little bow?