It's funny I don't think I've met a Smith in my life. Met plenty of Wang, Chen, and Tan when I lived at that part of the world though. Can I ask why Tan (Singapore and Malaysia) and Chen (Taiwan) are coloured differently? They're the same surname.
They are all different pronunciation of the Chinese word 陳. Chen usually is besed off of the Mandarin way, Chan is Cantonese, and Tan is Hokkin, another Chinese dialect commonly spoken in Singapore.
Most interesting one I see quickly is Kim in the central asian countries I assume from the mass relocations/deportations of ethnically Korean soviet citizens to central asia during WW2 and a more diverse set of names in central asia.