Shout-out to Immigration in Patong, Phuket.
Crowd of maybe 20 foreigners outside before their opening at 10am. Numbers given upon entry, the boss running a tight fastcraft, next, next, my tourist extension was done after 15 minutes and by 10:30 the entire place was empty, everybody had been served. Uncomplicated and efficient.
TLDR : Answer Summary
A user praises the efficiency of the Immigration office in Patong, Phuket, noting a quick process for tourist visa extensions. They report arriving before opening, receiving a number, and completing the extension in just 15 minutes, with the entire office empty by 10:30 am.