The irony here is that one of the weekly group rides with a smaller group with whom I am involved virtually disappeared a couple of years ago, because a couple of riders were blowing out ahead every night at a 20mph average, while a few of us were soldiering on at a 17-18mph pace (I among them), and the ride leader was recovering from health issues while also trying to stay with some newbies at an under-15mph pace... they would invariably cut the ride short every night, for fear of arriving back after dark.
Eventually, the slower riders stopped showing up completely (including the Captain), while I became the only moderately-paced rider, trying to keep of with the speed-demons, and I dropped the ride, as well. I would have kept with the ride, it being the first weekly group ride I attended faithfully after getting back into cycling, but it just sucks to be the only guy riding at a certain pace, blowing up trying to keep up with two or three others.