Thais are very connected to spiritual worlds. Gods and guardians are placed everywhere to make sure that there is something to hold on and look forward to. The divine powers may grant their wishes, give them strengths or, at least, ease their minds. The people are very good at making sense of this tangible world by referring to the beyond.
There are many ways to get in touch with those in the unknown territories. Burning joss sticks seems to be a symbol of making contacts and a tool for the communication. Spots where incense are burnt and stuck indicates the spiritual significances of the areas and the relationships of the people and their lands.