There is a Chinese restaurant in Chinatown London that is packed every night yet the staff are incredibly rude but the food no doubt is the business.
Won Kei, 41-43 Wardour St
London, Greater London
020 7437 8408
When I lived in London, it was like a right of passage to go here. Good to know that after all these years it is still there 
Unfortunately they tarted it up a couple of years back, may have lost some of its edge and charm. LIke filling the building floor by floor (5 of them) as the night got busier, queueing up the stairs, putting you on big tables with a group of other people you didn't know before the meal, and ignoring you if you dared to complain, or telling you that you've over ordered on the food, cheapest crockery and utensils, small glasses and beers/soft drinks served in cans, and I don't know which charm school the waiters went to, but customer service focused it aint. I loved it as it was, but like all these things some smart arse thinks you should change a successful formula, same as all the glitzy places in Brick Lane now, what happened to the old curry cafes with plastic tables??