Wirelessly posted (Samsung Galaxy S: Mozilla/5.0 (Linux; U; Android 4.0.4; en-us; SGH-T989 Build/IMM76D) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30)

It's due to inability of people to look beyond themselves. Your birthday,which occurs once a year, every year, is an insignificanrt event for others. In a group of 60 people, the probability of any two people having the same birthday is already more than 99%. My birthday, anniversary, or anything else is my private matter and I have no desire to share with strangers, some if whom might be willing to sit in my seat, hog my space or a shared armrest.
I don't understand why some people want attention from strangers.