I like to think of them as 'runs' not 'races' - takes the competative bit out of the equation.
As for the loo thing..... yup, me too. I think it is subconcious programming
. Either that or all the water I drink in the two days before - because 1. the books say you should and 2. to keep me on the straight and narrow by keeping my wine glass hand occupied.
Any way, whatever, I'm grateful for it, I'd rather deposit it than carry it round for 10k or 13 miles!!!!