Your first and only mistake was DMK. They are always questioning people there, everytime. Go to Suvarnabhumi ONLY if you have too many stamps in your passport. They don't even look at your passport at Suvarnabhumi they just stamp it and rush you through.
The groups are filled with two different types of people - Poindexter know-it-alls like Brandon Thurkettle or depressed angry old retired men with no lives.