Training slow is pro. Means you've got bigger fish to fry. If you're out on a leg loosening Friday evening ride before a relatively important Saturday crit, why chase some bozo who isn't racing? Or, if s/he is, then either you're way outclassed (so why bother) or you'll destroy them tomorrow (so why bother).
What's most entertaining is that you're going slow, they pass you, and they're dying to maintain pace. Eventually you either ride slowly past them or, more likely, they turn off so they can sit up.
cdr