"The Sages of Sivana have known the secret of happiness for over five thousand years. Fortunately, they were willing to share this gift with me. Do you want to hear it?"
“No, I thought I'd take a break and go wallpaper the garage first.”
“Huh?”
“Of course I want to hear the secret of eternal happiness…”
Source: Robin Sharma, The Monk Who Sold His Ferrari: A Fable about Fulfilling Your Dreams
The person who uttered those words is using a literary device called Sarcasm. In this particular case, the respondent is invoking ambivalence in the face of what should be an extremely powerful secret the first speaker is offering to share.
Amusingly, sarcasm can easily and readily backfire if the recipient of the sarcastic remark doesn't recognize it as such. What is absurdly obvious to one person isn't necessarily so to others. Everyone parses what they read and hear through their own background, beliefs, grasp of the language, and so on. Even native speakers can and will fail to recognize sarcasm.
So, to answer your question, the sarcastic remark can be understood as TRomano has already mentioned: Don't be ridiculous! Of course I do!
