I had an appointment this morning and the (very pleasant) receptionist greeted me with that line, to which I replied "Well, not really great, otherwise I wouldn't be here", which was met by a look of surprise.
What else did she expect? I was ill!
In a similar vein is the "Have a nice day!" that the checkout-chick throws your way at 5:30 in the evening.
In both cases it's habit, I know, but in the former "How can I help you?" and in the latter "Thank you." would be more appropriate.
