Skid Nazi's.
Imagine riding down a trail and you come in hot, jam on the anchors and your wheel locks. Skiiiiiid!
Man wearing what appears to be an SS outfit jumps out of the heather. Strides towards you:
"That was fun" you say
"Quiet" He barks
"You must not skid, have fun or even attempt any humour. If you do not start taking yourself way too seriously I'll be round with my mobile gas chamber!"
He whips out a pair of leather gloves of hits you around the chops. Very roughly indeed.
The Future.