No hair shirt required

Today I went to an early morning climate change event at a hotel about 2 miles from home. The event was about the carbon emissions in the North East of England and what could be done to tackle them. One of the speakers, who I've known for a couple of years, made a quip about me arriving by bike.

I cornered him later to point out (in a friendly way) that I didn't wake up this morning and say "Brilliant, I can save a few grammes of carbon by cycling!". Instead I looked out the window and thought "Brilliant, the sun is shining, I can have a lovely cycle up the river valley, listen to the morning birdsong, and get some light exercise while I'm at it!".

It was indeed lovely. When I emerged from the valley I spotted one of the other delegates bouncing over speed humps in his car, looking stressed. Who was wearing the hair shirt?