Savings?!?

I've just got back from the supermarket, its a place that is necessary to visit, but, in my opinion not a pleasurable place!
Up and down the aisles i went, bread, veg, rice, fish, milk, my trolley filled with foods to last me the week.
Now, the difficult part, which till do i go to? i must have spent at least 47 seconds weighing up the options, which till has the least people waiting? out of these tills which person is likely to be the fastest moving through? So i decide, till 21. Currently the patient check out lady is serving a middle aged woman, who has a daughter with her to help pack and carry. Fantastic, won't be waiting long here. They have bought a lot of stuff, )i don't like to think of myself as being to nosy, but when your in a queue you can't help but look at what the person in front of you has purchased) £179.20 the checkout lady says, the middle aged lady looks up hands her credit card across and then about 10 25p off vouchers??? she has just spent £179.20 and is now holding up the queue for a £2.50 discount. To top it off the till sticks, and we stand a further 5 minutes waiting for the 16yr old supervisor to fix it!
I know that every penny counts and every little helps, but flaming heck!!