I'm from Sweden, and a Swedish colleague met a team that visited from India. Half-way through the meeting she had to stop and ask why the Indian team were shaking their heads. It turns out it was a head bobble or Indian head shake.[1]
My colleague thought that they kept signalling "no, no, no" by shaking their heads while she was speaking, but it turned out to be the exact opposite. I'm very happy my colleague stopped and asked, because a lot of people would stay silent and keep their misconceptions.