The context of the following conversation is Casey took her dog out for a walk to get it some exercise on a nice day.:
Casey says I took my dog to Central Park yesterday..
The friend responds That's a good way to get some exercise..
Casey responds No kidding. The walk turned into a run pretty quick..
The friend responds Dogs aren't going anywhere, but they get there fast..
Casey responds We ended up on the East Side, I live on the West..
The friend responds East is East, and West is West, and never the twain shall meet..