My take on it is that it depends on if whatever utility you're putting your bike to at the moment slows you down from your normal 'recreational' riding speed. That's usually the case, but it doesn't have to be so. Say you're a messenger who has to hurry on the job but likes to take slower rides for fun and relaxation; in this case, the utilitarian riding you're doing is faster than your recreational riding. I know I ride more slowly on fun rides with my friends than I do on my commute.
By the way Cyclaholic, 24mph is really fast! I took 9th in a sprint triathlon two weekends ago and averaged only 22.7 on the 18.6 mile bike section. Do you train and race or ride a recumbent?