One thing that was completely new to me when I arrived in Thailand was the presence of Spirit Houses, seemingly everywhere. These are a characteristic of Southeast Asia, not just Thailand. At first I thought they stemmed from the Thai version of Buddhism, as 95% of the Thai people are Buddhist. But I later learned that these had to do with Animism, not Buddhism, an even earlier tradition than Buddhism for the Thai people.  

One good explanation about the Spirit Houses can be read here,  written by an expat teacher in Thailand. It seems like one of the most expert authorities on the Thai tradition of Spirit Houses is another expat, born in California who used to spend her summers in Thailand as a kid. She has an excellent description of the subject on this page.  She has a very extensive website about them, which you can explore once you've looked over her introduction to the subject. She was the first person who gave me any information about Spirit Houses when she appeared on the Bangkok Podcast (starting at 10:30) which I used to listen to a lot when I first got to Thailand. Listen to that podcast, it is quite excellent! I was very disappointed when that podcast came to an end. It was an excellent source of good information about Thailand.  

I have one disagreement with what Marisa Cranfill says on that page I linked to on her website up above. She wrote, "Virtually no building in Thailand is erected without an accompanying spirit house."  I know from my own experience that this is not an accurate statement, because there is no Spirit House on the property of my wife's family home and there never has been. BUT in the podcast there is a brief mention of a "consecrated pillar post" built into new buildings. My wife told me that her family home has a pillar post that was blessed by a monk from their nearby wat.  

I find this to be a very interesting aspect of the Thai culture. The image of Spirit Houses is from Wikimedia.