I have been to Thailand more times than I can remember, as it was cheap and convenient for my visa runs at that time. It is also the only country that did not give me any trouble whenever I entered and exited through Cambodia, Laos, or Malaysia either by land or air. Thailand truly lives up to expectation as a tourists' country - I hope it stays that way as it is an exotic place that has something for everyone.
On one of my visa runs, I was trying to choose between Chang Mai or Chang Rai and eventually decided to go to Chang Rai as it is less touristy. It is also very convenient to exit at Tachileik, Burma (now Myanmar) or Huay Xai, Laos and they allow you to return to Thailand on the same day. I took the night bus from Bangkok to Chang Rai and stayed at a guesthouse which included a simple breakfast of local food not far from the tower clock. I did not see any other travelers or tourists at the guesthouse so I thought "Is there anything to see in this place?" I was walking around to familiarize myself with the area and get my bearings when I came across a tourist office. I learned that there were Hill Tribe Treks, and some Golden Triangle tours, where opium used to be an industry.
I booked a trip on one of the treks that included, presumably, an overnight stay with a local tribe, dinner, opium smoking, and a massage. After dinner, we were all sitting in a circle to try smoking two pipes of opium which was included in the price - if you want more, there was an extra fee. I noticed it was mostly the elderly of the tribe, with teeth so black and red colored that I excused myself when it came to my turn. I also cut short my one hour massage as the massage mostly consisted of children jumping on my back.
Early morning, I asked an elderly guy to show me his opium field. We walked some distance away, then came to a garden with beautiful pinkish flowers. I asked if it was legal; he said it was allowed for their own use as they needed opium to make them strong so they could work harder - whatever that meant. I'm not certain that we understood each other really well, but he did speak English. Nevertheless, I enjoyed the experience and liked the people - they were really nice and entertained me, even if I didn't get my opium smoke.
Next was the Golden Triangle where I could see militias with machine guns guarding their opium trade or so I thought. I hopped on to a long boat to get to the point where the Mekong River borders Thailand, Myanmar, and Laos. The short boat ride was pleasant, and after taking some photos off we went. I didn't see any militias but did see other boats taking other tourists with maybe the same idea. We crossed Mae Sai to Tachileik, Burma for that important visa stamp in my passport . I just wandered around the area next to the border, though I was allowed to stay for 3 days if I changed enough Kyat (burma currency) but went back to Thailand the same day, and the same way that I came.