It was the first day at university and the young man was excited about the future that lay ahead. Whilst exploring the campus he turned a corner and nearly knocked over an elderly professor. "Oh my goodness" he exclaimed, "I'm so sorry professor!".

"That's ok son," the man said, "but I'm no professor - I'm a student and it's my first day here".

The young man was shocked and before he realised that he was possibly being insensitive he blurted out "But you're so old - I'm sorry - I didn't...