Carrie Lukas, writing for Acculturated:
The differences in the use of public spaces explain behaviors outside of the playground too. Americans find it jarring when they are sitting at a European café or restaurant and someone takes the empty seat at their table. If someone is sharing our space, we assume we have to interact. Europeans presume that they and others will enjoy privacy even in close quarters. Just as American parents teach their children to look people in the eye and politely greet them, European children are taught how to interact quietly to avoid bothering people around them.