Overpriced drinks and unbelievably rude waitstaff. If any of the people at my table hesitated for .001 milliseconds about what to order, our waiter (I kid you NOT) rolled his eyes and muttered something under his breath. It seemed he could not fathom how such uncultured, ugly Americans had somehow made their way into his hotel bar.
If you're staying at the Fairmont and have an hour to leave the hotel and grab a drink, try to get in to Dominion Tavern on Rue Metcalfe for one of their marvelous cocktails. Or, go to Nyk's on Rue Bleury for an affordable local beer or glass of wine.