The joy of McDonald’s when traveling is that you know it is a place where there is AC, water, and a restroom. In Thailand, there are a variety of McDonald’s. The mini-mart version that serves just the basics. The grab and go version that serves even fewer basics and is typically just a counter in a transit station. And of course the full McDonald’s complete with McCafe, wifi, AC, and a restroom.
Some unique menu variations in Thailand are fried chicken and rice, a chicken/vegetable dish served with rice and an egg on top, and a variety of pies, including corn, pineapple, and taro (I’ve heard about this but have yet to see it).
McDonald’s provides a good idea of what local tastes are even if it is a “McDonalized” version. The fact that McDonald’s localizes for every region and country makes it that more interesting to visit when traveling even if I never visit one back in the States.