All this is good as long as you realize that asking "Are you happy?" is <i>much</i> different than asking something like "Would you be disappointed if our product vanished?".<p>Your present wording will probably encourage a good number of default instinctive "yes" responses since it is a common question. On the other hand asking someone if they'd be disappointed if this was taken away from them requires a second of thought...and perhaps a more accurate response.
Microsoft did something similar with the beta of Office 2010 - they put a happy face and a sad face in the system tray with a pop-up menu with 4-5 expected problems/praises and 'other' as the last option. At first I got really surprised and thought it was some virus disguising as 'free' smileys.