All I can say is wow, went to get an extension at Chiang Mai immigration near the airport, got my ticket at 327pm, passport back all in order at 337pm, in an out within 10 minutes, hats off to immigration at Chiang Mai, prior I used to goto promenada and had to spend about 2 hours,
TLDR : Answer Summary
A user shared a positive experience getting a visa extension at Chiang Mai immigration, completing the process in about 10 minutes. This was in contrast to their previous experience that took around 2 hours at a different location.