*Beware of triathletes.
As a mountain biker, you've always been deeply suspicious of triathletes. As a road cyclist, you will find out you were correct to be so, and you will find out why. Triathletes will try to infiltrate your ranks (see photo) and join your rides, then demonstrate that they have no idea of how to ride in a group, and very little control of their direction of travel.
Most importantly, though, they wear these short shorts and tank tops that are just plain creepy.