The Invisibility Phenomenon

Now, I won't claim to have discovered this phenomenon, but I do experience it everyday, and I feel the need to comment on it.

I ride the train to and from work everyday. On this daily train ride, I have had the following 2 experiences almost everyday.

1) An elderly or pregnant passenger gets on the train. Noone moves. Finally, a young woman will get up and ask if the passenger would like to sit. Now, there is no shortage of men on the trains, but 9 times out of 10, it is a woman and a young woman at that (I'd say younger than 35) who gets up. I don't understand this.

2) People line up or queue (depending on where you are from) in order to get on the train. There are clearly people who have been waiting for a while (longer than you), yet it never fails that someone from the back will squeeze their way through and try to get to the front. Or just step in front of someone who has been waiting in line and get on ahead of them.

I call these two things the invisibility phenomenon. Why on earth do people think it is OK to behave like this? I really don't get it. Do you?