On Being Old

Some years ago, not long after my 80th birthday I was on the tube travelling from London Bridge to Eauston. The Underground was crowded, people everywhere. I dragged my wheelie case aboard and clutched hold of an overhead strap as we accelerated out of the station trying not to bump into anyone. 
A young man sitting nearby stood and said, "Sit down, sir, take my seat."
It was the first time that had happened to me.
​It was because I am old.