The subway car is filling up, so I'm planning to take my bag off and place it next to me so that an elderly person won't sit next to me.
Isn't that rude? Why don't you want an elderly person to sit next to you?
It's more comfortable if I can sit alone.
You don't have the right to stop people from sitting next to you on public transportation. That elderly person will be very uncomfortable standing for the whole trip. Let anybody that wants to sit next to you do so.
Why should I have to listen to anyone? I do what I want.
But you are in public, so don't you think it'd be best to maintain a good public image of yourself? The elderly are wise and have been through a lot, so don't you think they have done enough to deserve a seat?