We could have been much more advanced if Christians hadn't been so intolerant and discriminating through out history. They have destroyed many things of great value, not only from the Mayan culture. Things that we could have benefited from greatly. The Romans knew things that we have had to...
One example, looking people in the eyes (or face) while they are talking is rude in some cultures while it is polite in others. Knowing the culture you deal with will make things flow without misunderstandings.