But I don't understand the whole 'only buy what you would have bought anyway' idea on this thread - I bought different, better things because they were reduced and therefore I could afford to! 
If I'd avoided the shops today I would either have to pay more another day, or get less good gifts. I did buy a couple of treats for myself too, but the last time I checked, shopping wasn't a cardinal sin.
Fwiw I didn't see any pushing and shoving in the shops I was in, mostly clothes shops and department stores in Central London.
Eg I would much rather have shopped online for Gap stuff , but the discount was 50% off everything in store and the online discounts weren't as good, so yes I did get there early and make a beeline for things I wanted.
I saw lots of people delighted with their bargains and enjoying themselves - some flagging and sitting in the aisles having a drink of water, but I don't recognise the brutish behaviour mentioned on here at all.
I think it's a quite snobby attitude from many (not all) posters on here tbh. Nothing wrong with America, and nothing wrong with having a sale at a time which actually suits a lot of people - Jan sales are all well and good but not for Xmas shopping!