Myanmar. Thai Embassy, US Passport holder. Required proof onward travel (my case, bus ticket), and fee. Nothing more. Drop off 5 minutes, pick-up the 5 minutes. They require US currency that is crisp new - $40. Overall good experience. Yangon is a nice place and the people are nearly as friendly as Thailand.
TLDR : Answer Summary
A US passport holder described their experience obtaining a Thai tourist visa at the Thai Embassy in Myanmar. They reported that the only requirements were proof of onward travel (a bus ticket) and a fee of $40 in crisp US currency. The process was quick, taking about 5 minutes for drop-off and pick-up the next day. Overall, they had a positive experience and noted the friendliness of the people in Yangon.