The biggest city in the world question you were being asked was a little misleading. The answer relies on a number of factors. One being landscape by area, which is never flat and level. You were clever not to answer it.
Yay, love you whoever you are. I don't even know or care what it is lol
You may not be a psychologist but I respect your opinion and I'd like to hear it. I can't stay single and happy. If I'm not content unless I'm in a relationship. Do I have a problem that I need to look at?
Find the right person to be in a relationship with. Single does have it's advantages. Embrace them!