Of course people should 'move fast', unless of course they should actually move slowly, or move glacially, or move moderately quickly, or with utmost urgency...

Of course people should 'move fast', unless of course they should actually move slowly, or move glacially, or move moderately quickly, or with utmost urgency... the trick is knowing what's actually right, isn't it? That's where the metaphor breaks: this isn't like driving a car where the right speed is obvious.