'All right,' he snarled. 'You've had your fun, you've ruined my life, now get back to where you belong!'
'But I--' protested Twoflower.
'The Spell, I mean the Spell,' said Rincewind. 'Go on, get back on the page!'
"But I'm not even a proper wizard. You threw me out, remember?"
"I can't think of any student less able," said the old wizard, "but you're here, and that's the only qualification you need. Come on."