We MUST try to stay calm, smile when things get put in your way.
Thais must show how strong they are by requesting one more thing is required, this is part of their culture and it shows where they and you are in the hierarchy class system.
we should not question them, we should only reply by saying "I'm sorry I don't fully understand you are truly an expert in your field of expertise, I am truly beneath you, thank you for correcting me"