Bastion is Old
Nobody alive remembers when Bastion wasn't the hub of mankind. Trends have come and gone, buildings have risen and crumbled, and regimes have fought to rule every corner of the city with one failure after another.
Bastion is Difficult
Nobody will help you out of the goodness of their heart. Even when they're on your side, they want their own things. Some people are even just out to mess with you.
Bastion is Ugly
If somebody builds a beautiful building, somebody will build a brutalist prison next to it, or maybe brown weed will crawl up its marble walls. Smog paints everything green-grey, and nothing stays pretty for long.
Bastion is Confusing
Nobody knows who's in charge. Lots of people claim to be, but the city is too large to rule. For every possible claim there are at least two rivals.
Bastion is Full of Obstacles
Getting from one street to the next can be an hour long slog through knee-deep sewage, or a twisted crawl over a skybridge. There are taxes and tolls for everything, and every imaginable law is being enforced by someone or other.
Bastion is Full of Lies
Don't believe everything you hear about Bastion. Often it's a rumour. More often, it's worse.
Bastion is Always Changing
Fashions, property ownership, slang, laws, culture. Everything is always changing.
Bastion is Unplanned
Maybe it was once, but now the layout makes no sense at all. Who builds a school next to a brothel? Who points the main artillery guns inward on the city?
Bastion is an Environmental Nightmare
Smog, rivers of sludge, tanks of molasses. If there's a waste product, Bastion has it. The weather is all over the place. Steaming hot summers, and frozen winters. Droughts, and monsoons. Don't expect to see the stars all that often.
Bastion is Over-Engineered
If there's a possible problem, a dozen rival engineers have tried to solve it. There are too many tram networks, and none of them work well. Underground walkways, elevators, automatic stairways, most of them not maintained well. Factories churn out things that nobody needs.
Source: Inverting the 10 Principles of Good Design