Greetings It is not customary to greet strangers in passing (eg, on the sidewalk or upon entering a shop). Don't be offended.
Small Talk Bostonians also might not feel like chatting while riding the T or standing in line. That said, most locals will be more than happy to give directions, answer questions or otherwise help out.
Boston Accent If someone speaks with a Boston accent in Boston, it's not news. No need to mock, imitate, or even comment.
MBTA Etiquette Stand on the right and pass on the left on escalators. Allow passengers to exit the train or bus before boarding. Offer your seat to the elderly and to children.