Much of the human enhancement literature focuses on the ethical, social, and political challenges we are likely to face in the future. I will focus instead on whether we can make decisions to modify ourselves that are known to be likely to satisfy our preferences. It seems plausible to suppose that, if a subject is deciding whether to select a reasonably safe and morally unproblematic enhancement, the decision will be an easy one. The subject will simply figure out her preferences (...) and decide accordingly. The problem, however, is that there is substantial evidence that we are not very good at predicting what will satisfy our preferences. This is a general problem that applies to many different types of decisions, but I argue that there are additional complications when it comes to making decisions about enhancing ourselves. These arise not only for people interested in selecting enhancements but also for people who choose to abstain. (shrink)