I can't say that Thailand was an unequivocal thumbs-up, from my perspective. Rather developed and Western, it was less exotic and less charming than Laos, or even Vietnam. And with tourism a long-time staple of the economy, the mindsets have been altered by the goal of deriving as much profit as quickly as possible without, in many cases, the foresight of working to generate goodwill that bears more sustainable fruit.
The former Lanna Kingdom, in the North, was a relatively smooth transition from Laos in terms of its culture and attitudes, if not the state of its infrastructure. The people here don't look much different from those in Laos -- light skinned, slim if not small, looks clearly influenced by its Northern neighbors. Yes, Northern Thailand was more developed than Laos, but there was still plenty of that genuine friendliness tourists site so often... or at the very least, realization that a satisfactory service needs to be performed in order to entice tourists to open their wallets.
I skipped Central Thailand when I rerouted my trip due to the floods, so for a good three weeks out of the four that I spent in Thailand I was in the South. People here look quite different from those around Chiang Mai. They are much darker skinned, many looking more Malay (in my understanding of what Malay looks like) than Chinese. There is a lot more chubby people here than in the North. And unlike the predominantly buddhist North, the South is predominantly muslim, with a fairly high percentage of them rather observant.
The South, I have to say, under-delivered. Sure it has some beautiful beaches (I think Koh Tao was my favorite, if I had to pick a place to spend a week). However, not only is the general price level meaningfully higher in the South than in the North, but the attitude you get in return for that higher price tag is a lot less positive. Simply said, the South ha gotten fat and lazy off of tourists. And it's not to say that it's the case for every single establishment, but overall, they've gotten spoiled rotten by tourists practically begging to give them their money and gotten corrupted by the revolving-door mentality. I haven't been asked the question of 'how much can you pay?' anywhere else in the world other than here, where taxi drivers, for instance, don't even make an effort to disguise their attempt to gauge you. I'm all for market economies, anybody who knows me even a little knows that, but when a shared-taxi / bus driver attempts to get a price from me that's 8x what the published fare is, that's just not cool in my book. In the South, you often don't even get a smile or even an acknowledgement as you part ways with your money -- the explanation I heard is that it's not traditional for Muslims to smile.
The 'land of smiles' moniker needs to be addressed more in-depth. It baffles me how so many people can confuse smiling with friendliness. After all, most are familiar with the world-famous 'American smile', the forced expression of showing one's teeth while not necessarily finding anything particularly joyful in the moment. How is it that the Westerners are able to recognize insincerity in that smile, yet are so oblivious to the Thai smile? Smiling is a social behavior, rather than a reflex. Monkeys smile to express a variety of emotions, and friendliness is not even near the top of the list. I read that Thai people have 13 different types of smiles, of which the genuine happy smile is only one of the many meanings. I've seen some of the least-masked 'I-smile-because-I'm-expected-to' smiles here.
Overall, I was a bit disappointed by what I saw relative to the travel stories I heard. The ability to observe a culture as it once was is no longer possible, at least not if you step anywhere near the tourist trail. Don't get me wrong, this is still a great place to go on vacation, and even at prices inflated 8x relative to locals' costs you will probably still find it reasonably priced if not cheap (and most likely, will never even find out). But, my North American readers, keep in mind that Thailand's glories are perhaps a bit inflated by sun-starved Europeans who don't have the luxury of having Latin America a quick skip away for an impartial comparison. And those of us who do, we should spend more time exploring it rather than chasing a 'crowded trade'!