I opened 20 some odd locations...and the worst to staff was the NYC area stores (Brooklyn was all mine, with the help of another trainer and a close friend at the time...)...Queens and Bronx were both nightmares as well though...
Finding people who actually give a crap about what they are doing is so difficult in larger cities. They always want to be more than what they are, and don't realize that work gets you there. Smaller cities are more ripe for the picking, though that depends on the area as well. SC, for example, is just a sump-hole with respect to that...
Muskegon, I literally had people BEGGING for jobs, and taking it all very seriously. Same with Superior, CO (and Superior isn't exactly small town). SC, I had people who had been unemployed for 2 years telling me that 1 buck above min wage was too cheap, so they turned it down (with no skills to present)... <facepalms>
Long story, but it's a dynamic I found very interesting...