Why do clerks in stores or shops in the UK mostly just ring you up and bag your item and say nothing really>?

I spent a year in the UK and by the end of the year was so tired of UK customer service. Cab drivers, bartenders, store clerks, waiters/waitresses, dry cleaners, etc. were all rude and acted like I owed THEM my business. I was glad to come home to a more civilized country where people treated you with respect.