First of all, there is no driver education. People simply buy a vehicle and start driving, imitating what others do on the road. Therefore many of the concepts with which most foreigners were introduced to are unknown. Some of these lead to danger.
Thailand has one of the highest motor fatality rates in the world. The people who die most often are riding scooters. There is a helmet law here, but it is sporadically enforced, and almost universally ignored by young people who put great stock in seeing and being seen by other young people. So they put more effort into their hair and makeup than in protecting their heads from accidental injury.
Likewise, rear view mirrors on motorcycles are used for checking makeup and hair, not for looking behind before entering a roadway. In fact, almost nobody ever looks behind them, either by turning their head or looking in the mirror when entering into a stream of traffic. It’s just assumed that those coming up from behind will give way. Thais are big on merging.
There is no concept of right of way, which Westerners find infuriating and puzzling. If someone slides into your lane no matter how closely or unexpectedly, that’s just part of life. Because right of way is unknown, there is no incentive to choose a lane or to stay in in it. Signaling is rare.
In Thailand hardly anyone honks their horn. To do so would be impolite. In Vietnam, a much more aggressive place, horns are honking constantly. In fact, when I rented a motor scooter in that country, the first thing the person I rented it from showed me was the location of the horn.
Crosswalks are universally ignored. Even if those attempting to use a recognized crossing would press the button, wait and get a WALK signal, they would be foolish expect traffic to stop. Sometimes it seems that zebra stripes are a cruel joke, a way to herd targets in close proximity. Watch here:
Pedestrians cannot safely assume that they have any rights, and because any sidewalks that exist and almost always clogged with someone trying sell something, sometimes even the tables and chairs of a roadside restaurant, or a parking lot for motor scooters, pedestrians usually don’t bother to try to ambulate on sidewalks at all and simply walk in the street.