JCC The Foul Places of The Earth

Stockholm. Sure, not everything about Stockholm is bad. There is some gorgeous architecture, several great museums, and a nice coffee shop or two. But the negative with the city far outweighs the positives.
People are so stressed out they run down the escalator to catch the subway train - even though another one leaves three minutes later. It's basically impossible to find people there who aren't incredibly rude and condescending towards us country-folks (no matter how large a city you live in, you're still essentially a hillbilly to Stockholmers if you don't live in Stockholm - and they'll gladly tell you that).
Everything is crazy expensive, it's difficult to find good food, and the public transport system is broken beyond repair. Most friends I've had who have moved to Stockholm have gone through a complete personality transformation. They become noticably unhappy and angry. They tend to change back though, if they move away. So there's something about that city that turns people into depressed jerks.
In short: I ****ing hate Stockholm! It has everything bad with Sweden, dialed up to a hundred - as well as a lot of problems completely unique to Stockholm.

London. Basically the same as Stockholm, except the architecture is even more lovely. Oh, and unlike Stockholm, it smells. Really, really bad.
Apparently trashbins haven't been invented there yet.

 

Let me clarify - I don't hate London the same way I hate Stockholm. There are more positives to London (and I don't travel to London two-three times a years as I do Stockholm, which works in London's favour).

But that smell. Seriously - people just leave their garbage on the sidewalk. It stinks in London.
And the food is both expensive and... bland at best, awful at worst.

As for the best - Berlin is the best. I'm quite fond of Tallinn as well, and Gothenburg.