Unfortunately Dai's situation is probably not too uncommon. The bitcoin site still guides new users to enabling "generate coins", and the software has the tickbox in an obvious place in the GUI. Reading the site, it's not surprising people think bitcoin is all about mining.
We should really try to write a new introduction for the main bitcoin page that puts less emphasis on mining and more on the trade aspect. Also, remove mining from the official client!
too many people think mining is the whole point, or even the biggest point, of bitcoin.