The group rides I did over the summer would occasionally see semi pro riders tag along just to taunt the rest of us. Hell I had a hard time keeping up when they took off. We would carry 27-30 for a mile or two, a couple of guys hammering up front and the rest of us scattered out over a quarter mile with numb legs and no breath. Makes you think about how hard it is to race in Pro,1,2 races.
There was also a pro or semi pro tri chick that would come out on the flat rides. She could carry major speed for a long time. We had a tandem show up one week that kept going off the front. She got tired of them doing that so when they hammered off the front on a stretch that was free of stop signs for a few miles she said something about the tandem pissing her off and there she went. Probably carried 30+ to catch and pass them. The looks on the tandem rider's faces were priceless.