Have you ever visited a city and felt an instantaneous click? Walked off of an airplane or stepped out of your hotel and felt happy, excited, at home?   Is it the architecture, the weather, the croissants, the vibe? Why does one person adore San Francisco while another finds it utterly unappealing? I’ve found myself having conversations like this one on more than one occasion:   Me: So what did you think? Isn’t San Francisco amazing?   Friend: It was okay. Kind of dirty. I didn’t really love it.   Me: (Look of confusion) But what about the water, the hills, the cable cars, the colorful houses, the, the…you know…the vibe?   Friend: (Shrugs) It was just okay. Not my favorite.   Me: (Wonders…