Your response to questions such as these would probably depend upon the intent of the person making the assertion. Is their comment intended as a compliment on your intellectual ability or is it intended as a “putdown?”
Your interpretation of their intent will be based upon the relationship you have with that person. If someone who is close to me and whom I trust were to say, “You’re too smart for your own good,” I would laugh and say, “Or maybe, I’m just not smart enough.” This self-deprecating remark is a friendly acknowledgment that I recognized that I have done something that is self-defeating.
However, if I judge the comment to have been made in a derogatory vein, I would answer something like, “Yes, it’s lucky I’m not a genius, because then I’d be in real trouble.” In both cases, it’s important to avoid a defensive response, especially if you feel that the comment was made as a putdown.
The comment, “You’re too intelligent to be happy,” is probably an intended as a humorous comment from a friend, or a philosophical observation about the challenges of high intelligence. One of the philosophers of Ancient Greece asserted, “To think is to be sad.” The implication is that high intelligence coupled with deep reflection make a person aware of the transitory nature of life and our purposeless existence. Another version of this is Thomas Gray’s poem in which he asserts, “Where ignorance is bliss, ’tis folly to be wise.”
If this comment seems to be made as a compliment, I would extend the compliment to include them by saying in a jocular tone, “Ah, it is indeed our cross to bear!” In formulating a response to such comments, the substance of the comment is not as important as the intent of the person who issues it. You know whether or not you are intelligent and whether or not someone acknowledges this is not significant; however, their reasons for issuing the comment contain more useful information for the tone of your response. For reasons why someone might issue such a comment, visit: Are you too smart for your own good? – Intelligence and IQ