I'm going back home to Virginia for the Thanksgiving holiday and I'll be taking a taxi to Boston Logan. I've noticed that in the past, the cabbie tends to take a longer route, and I was wondering if was bad etiquette to dictate which route I'd like him/her to take.
EDIT:
Wow. I want to thank everyone who's answered. I just got back in Boston today and I was so busy during the Thanksgiving holiday I completely forgot about this question. Seriously wow. You guys here at Travel Stack Exchange really know your stuff :)