My problem with non-helmeted cyclists
(other than their apparent suicidal tendencies) is that they always tend to go very slowly, which they think will stop them getting into trouble, or being hurt as much when they come off. This means I constantly have to overtake them, thus putting myself at greater risk. I don't cycle fast (my bike's too shit to get much above 20), but helmetless bastards might as well walk.
( TV's Nosemonkey, Wed 11 Aug 2004, 11:44, archived)

I don't think I cycle any slower without a helmet
unless it's a subconscious risk thang.

Getting hit by a bus is likely to hurt whatever speed you're going at.
( Newington HM Time Corps: Quo vadimus non requirimus vias, Wed 11 Aug 2004, 11:47, archived)