Ok I think I have worked out the correct formula:
Dislike = {N x [(a + t + m + l) x r x d] - (f + b)} x c / h
Where:
N = number of bikes
a = number of rides per week
t = time spent working on bikes
m = money spent on bikes
l = loss of holidays/weekends caused by working on/riding bikes
r = rarity of bikes and parts
d = dirtiness/muddiness of bikes and kit
f = fun had by spouse on or around bikes, this number can be and often is a negative number so remember this in your working out.
b = brownie points earned - scored for school runs, shopping trips, family outings when there's an MTB race on locally etc.
h = Hours in a Day.
c = some indeterminate female factor constant that varies in direct correlation to the phases of the moon and can increase the intensity from annoyance to wild hysteria. The constant can be determined precisely by plucking any number from thin air and randomly multiplying it by another large number.
Righ off to test my hypothesis. 
