If PCs were smart and honest, they'd say:

• "I'm not smart enough to do this for you. You're on your own."
• "You're about to delete a document you've been editing for hours. It's illogical that you'd wanna throw away so much work, so I refuse to delete it. In fact, I made a backup."
• "Your IQ is higher than that of a trained simian. So while you logged on as a new user, I'm gonna assume you can operate a mouse."
• "I'll now spell check your document. Please be aware that I usually can't tell if a word is misspelled if the misspelled version is in the dictionary."