Originally Posted by Peter Henry

I agree that is very probably a mental strain thing. This will be due to the possible higher degree of concentration needed on your daily commute.
I found that after our hoon to jerez at the weekend it took me until yesterday to start coming around a bit.The factors that created this sensation I believe where:
1.Several km of very slow negotiating of cars etc with other bikes moving in from all angles.
2.Needing to keep an eye open for a pal who had no idea where he was!
3.A beautiful but very taxing ride,(of about 2 1/2 hours) where you could not afford to let your mental defences down.
4.Having my son on board as pillion.
5.Being way too far along the road to old fartiness!