I didn't know the city at all, but I was so happy to be in New York I cried. I was so excited.
If you've lost focus, just sit down and be still. Take the idea and rock it to and fro. Keep some of it and throw some away, and it will renew itself. You need do no more.
When you're young, try to be realistic; as you get older, become idealistic. You'll live longer.