Possible Clues:

• Dismissive remark
• 'You're delusional!'
• "Don't you wish!"
• 'Oh yeah, that'll happen!'
• Irishman shortly to be attended by doctor? That's unlikely to happen!
• "Like that'll ever happen!"
• ''You wish!''
• ''Get real!''
• That's unlikely! (colloquial)
• "It'll never happen!"