"The Emissary" - the TNG ep, not the DS9 pilot. Despite the incredible hotness of Suzi Plakson as K'hlar, if I wasn't working out at the time, I'd have nodded off. It came off as boring soap opera that didn't make a ton of sense.
I always find great warrior cultures or cultures that knows how to fight when they have to fascinated. To fight well you don't just learn how to weal a sword and some weapons, but you also have to be able to understand how human thinks and react in time where you life might be jeopardized. If You teach someone how to fight but didn't train them how to handle the stress when the enemies are coming at them trying to hack or cut off your head, most people would freeze up and piss and crap in their paints or run and piss and crap in their paints at the same time at the first sign of troubles.
A lot of the fighting forces that ancient Thai people selected were comprises of people who don't feel frighten at the sign of danger and get sick at the first sight of dead or dying people where there are a lot of blood and guts and the smell of rotten corpses. They can think clearly in very stressful situation when they were under attacked. Usually, these people would take up job as the high ranking commanders who would always get into hand to hand combats with the enemies and give orders to the troops during combats, or some of the smarter ones would offer their services as espionage and assassins to the aristocrats and the royal family. A lot of these people are marked by high intelligence. They are not dumb like most people think. And they were often in charge of training the Thai armies and peasants who were drafted to fight. They would often manipulate people mentally and psychologically and train them how to be strong and how to handle stressful situation...kindda like how the U.S. marines train their men today to prepare them psychologically. Often time they would gave reasons why they need to kill the enemies and portray them as killers and that they would be fighting for a great cause. These people are the kind of people the Roman also chose as centuarians to lead their troops and these people made up a pretty decent part of their armies. The Burmese couldn't figure out how Thai people were able to fight so well and in a lot of cases they were pretty scared. A lot of their commanders were executed because they fail to destroy a much smaller Thai forces and some of their commanders litterally were scared shitless. It pissed the Burmese off that they were a warrior race and they couldn't defeat a bunch of peaceful people. Some of these people and volunteers also led a lot of suicide missions to slow the advancing Burmese forces and to psychologically intimate them. Most of the time it worked. The Roman armies also had the same reputation for being stubborn and pig headed and none of their enemies know what they were up against.