Financially Thais live for the moment while for Chinese save for future. It's basically a difference in lifestyle, except the Chinese are probably wealthier and able to make more of the moment anyway. But I doubt they would fit the Thai's definition of sanuk. The word 'sanuk' probably holds the key to the character of Thais. They like you if you're sanuk and don't care for you so much if you're not.
Get a letter from your doctor saying you take the Tramadol for pain. Don't produce it unless you have to which would be about 1 chance in 100 -no one gets their bags checked on arrival. Don't listen to people who say you can buy them over the counter. Tramadol used to be available and perhaps still is in some places, but I personally tried to buy it and met with no success. Codeine products you can't buy. Bezodiazepam was aavailable ove the counter 30 years ago, but now would be a drug you would only get through a hospital. Thailand is really down on the heavier pain and sedative medications, while antibiotics etc are freely available over the counter. Bring it with you. You won't have a problem. No one will look at your stuff, but if they do, you have your doctor's letter and the pills are in their containers with prescription details attached.