When we think of culture shock we often consider the challenges of immersing ourselves in a new language or a place with vastly different ideological values. But some of the most intense disconnects show themselves through differences in expression and body language.
A nod or glance that is considered a compliment in your home country can be perceived as a threat somewhere else, and the same applies to turns of phrase. In many cases, the quickest way to learn the cultural no-nos in a new country is to accidentally mess up.
In Brazil we are very pro-hugs even with strangers depending on the situation. Like tight hugs.
We have no problems about touching as in the shoulder or arm while talking, or side hugging to take pictures with strangers. We also have the kissing thing (not between men tho).
We share our life story and feelings with strangers pretty easily. Waiting-in-line-together micro friendships are a thing.
There are many cultures where this level of touching and sharing would be considered incredibly weird.