Another Slashdot reader since 1998 here. Not for much longer, presumably: if Beta stays I will most certainly leave, as may others will, no doubt. Appalling.
The reason why talking to your computer is somewhat creepy is that we do perceive our computer as an extension of ourselves: the mouse pointer is "us" pointing, Google is an extension of our memory recall power, and so on. The interface is designed to be non-intrusive. Now, talking to your computer would become like talking to yourself. It's mildly creepy since it involves in the best case a split personality, or alternatively the feeling that you are the one who doesn't know squat, and has to ask to someone else. Not nice.
The approach is conceivably different when you ask "Earl Grey, hot". In that case you just give a command in order to receive an item, and who wouldn't want that?