We live in Vancouver. Somebody told me that there were people speaking 70+ languages in Vancouver. I think it is more than that.
Each immigrant comes from a country with its own culture. For many years I’ve been interested and studying (whenever I could) different cultures and even have been trying to perform some comparative analysis. Recently I learned that there’s an entire branch of science called “communicative behaviour”. They study many different elements of communication, not language only.
A few things I know for quite a long time. For example, the distance that people keep when they talk or when they approach strangers is quite different in different cultures. If you observe a Chinese and a Canadian born guy standing and talking for a while, you may notice a strange dance: they try to keep the comfortable distance, which is quite different for them. What I did not know, that these distances are already measured based on some representative sample.
If you work with a team combined with people from different cultural background, you face a true challenge. I have heard several times that somebody interrupted other guys during a discussion, that he did not listen to the very end of what the other team member was saying. How rude! you would say, right?
Well, in some cultures, for example Russian - you know I’m Russian 
- or German interrupting other people is a way to show that you are engaged in the conversation. If you sit quietly and just listen, in those cultures it would mean that you are bored.
One funny memory. One of my architects was facing a challenge: the developer working for a customer was very rude: he was suggesting that my architect did not know what he was talking about, and he even was yelling. I suggested that my architect yelled back. It worked! In the culture of that developer (I forgot exactly which one, say, Russian or Italian) increasing voice and yelling means often deep engagement in the conversation. If you yell back you will be listened. Otherwise, you won’t.
[Note. Don't yell at me, I'm not Russian anymore. :)]
Some cultures created a extreme intolerance to strong smells. If you show up in such office wearing a perfume that is not an ordinary one, for example, the one that some orient girls like, you will be in trouble. Interesting, that India, China, oriental world in general are much more tolerant to the smells than North Americans, for example. Well, there are certainly exceptions.
Shaking hands, patting, kissing, hugging and all other ways of greeting and showing interest in another person are also different. In some cultures you may look a macho and in others you will look a gay doing just the same thing.
Being a leader is not an easy task. Pay attention to details. And most importantly, never judge based on the perception.