I know you would never be rude to a front desk clerk, but if you want more reasons than civility to treat these folks well, read Confessions of a Front Desk Clerk. And you know that rumor that you get worse service if you book through a third-party Internet site? He says they're true:
Hotel managers can't stand it when guests reserve rooms through Expedia, Priceline, or any other booking engine, because after the Internet site takes its cut, the hotel barely makes a profit on the booking. As a result, guests who reserve directly with the hotel receive far better service. When things go wrong--we've run out of rooms with king-size beds, or the hotel is overbooked because some guests extended their stay--the manager's first question is, "Do we have any Internet reservations?"