Markets, it is said, are good because they allow people to choose consumption bundles that are best for them according to their preferences and taking into account their budget constraints. However, what is good about markets if people have inconsistent preferences and are prone to behavioural failures, that is, when people choose options that may not be "best" for them? Robert Sugden (2004, 2012, 2017) argues that what is good about markets is that they offer opportunities to people such that they are free to get what they want when they want it --  even if their desires are not leading to consistent preferences. We discuss the "evolution" of the opportunity criterion as presented by Sugden in recent years and will point out the advantages and limits of his approach.