In the US:
Detroit
Washington (outside the "pretty" areas that is)
Philadelphia
Trenton, NJ
Newark
Gary, Indiana
Buffalo
Richmond
Phoenix (too much growth, traffic, "road rage" in the heat)
Houston
Around the World:
Manila
Rangoon
Jakarta
Bangkok
Calcutta
Guatemala City
Juarez
Matamoros
Mexico City
Rule of thumb: if you're in a "third world" country, the capitals are generally the worst as far as pollution, traffic, chaos and hassle--generally major "growing pains" due to mass migration from the rural areas being more than the city can handle; however the smaller cities (Mandalay, Burma; Chiang Mai, Thailand; Guadalajara, Mexico; Quetzaltenango, Guatemala) can be very pleasant places.