A sub of a fantastic kind
"WOW, this is subtastic!"
Originally from the comedy sketch show 'The Kids in the Hall', "subtastic" conveyed the idea that the speaker was about to say 'substandard', but quickly changed his mind to 'fantastic' after smelling the wonderful aroma conveyed by the subject of the conversation.
"I've called you into my office to talk about your poor performance at work. Frankly, your work has been sub... quickly changes his mind ...tastic!"