We’ve all seen it: a guy on a bike at a stoplight will periodically rev his engine for no apparent reason. A few days ago at Daytona Bike Week, I witnessed a rider doing a U-turn while holding in his clutch lever and constantly blipping the throttle. Because the engine was always at a different speed, the bike lurched each time he engaged the clutch. Then there was the woman riding the custom bike with ape-hangers so tall that she looked like she had to stretch to reach them. Still, at every stoplight (I was stuck behind her for a while), she’d pull in the clutch and vroom-vroom-vroom. Although the straight pipes were noisy, I think it was her tube top and riding position that triggered all the extended looks.

This behavior isn’t just limited to rallies, either. I see riders around my little slice of suburbia on the other side of the continent doing the same thing. So, why do riders do it? Listed below are some of the reasons we’ve come up with. Let us know what we’ve left out in the comments.