Because the cant pronounce Worcester or Gloucester....Now I'm not trying to be an Athol, but they don't know what the Hull I'm talking about....
The same reason when you talk to someone living outside of Canada, when you say you are from Canada, they think you live in Toronto! LOL
Why does everyone think if you live in Michigan, you live in Detroit? Or in Illinois, you live in Chicago? Same reason. Most well known city in the state.
It's a safe assumption, given that 70% of the population of MA lives in greater Boston.
What else is in Massachusetts besides Boston? ^_^ I'd only go to Boston for the tea anyway! xD
What is one thing that you can think of besides tea?