1. When you drive down a highway behind another car for a fair amount of time but feel no need to overtake it, because your speed match almost perfectly.
2. When you swim in a pool, behind or ahead another random person and neither of you feel the need to overtake one another throughout the entire session.
1. Oh damn, my speed buddy just turned away. It was rather comfortable to drive behind him. I guess now I'll have to watch my speedometer.
2. I really hope I'll find some speed buddies in the pool today, they always prevent me from resting on the edges.