I remember my first sojourn. Who hurt you bro? It's the land of smiles. Drop the tough guy act. If you don't have an extensive history of staying here then why would IO care about a return flight etc. You're clearly new here. Best of luck
I'm not sure how it works in Chiang Mai. A couple of banks knocked me back too at first. Then I walked into the head office and they didn't fool around at all. I had to ask my condo staff for a new 12 month lease and had that with me. The smaller branches make up their own policies. I recommend this one
Wear sensible shoes so you can protect yourself. Somehow made it 7 year without being bitten. Use your big boy voice to assert yourself has always done the job even in packs