Thailand is a Buddhist country - something like 95% of Thais list themselves as Buddhist on surveys. But animism still has a strong hold on the country, and it walks hand in hand with Buddhism. This leads to some interesting sights: huge demon guardians protecting the gates at Wat Phra Kaew come to mind, towering six or seven meters in the air.
One of the most widespread side-effects of this is spirit houses. When you build your house on a piece of ground, you're effectively evicting the spirits who live there. It's necessary then to create a place for them to live - if you don't, they'll become upset and bad things will happen. Generally, the bigger the structure you build, the larger and more ornate the spirit house should be - a mall will have a very large and very nice spirit house on a corner of the property. Seen above are the spirit houses for the Siam Discovery mall. They are very classically Thai; teak, and up on stilts, as Thais used to build next to rivers prone to flooding during the rainy season - most spirit houses are actually more colourful than this, but not so ornate. Apartment buildings often have a spirit house up on the roof. The spirit houses aren't just built and neglected: some people bow namaste to them as they pass, and some will pause to burn incense, place flowers, or leave drinks or meals. All of this is in the heart of busy, urban Bangkok: I imagine the practice is even more strongly supported in the countryside.