North American and a few European countries are monochronic, while the Middle East, Latin American and Sub-Saharan Africa are Polychronic. Not to use communication jargon but monochromic cultures are developed to be punctual, work on one thing at a time, don't like to be interrupted; they focus on personal efficiency rather than organizational goal in their daily life. To this group, time is linear. On the polychronic end time is cyclical. Punctuality is not very important and interrupting a busy person is not a bad thing as well.
In Lagos, Nigeria where "time is money" there are large elements of polychronic culture. I believe it's the same for other big commercial cities in Monochronic cultures. In Lagos, due to the large population density, unending traffic congestions is a way of life. So you have to wake up early daily so you can get to your place of business in time. I also feel like globalization has greatly influenced monochronic cultures to be polychronic in their business dealings especially in the corporate world.
If I tell you my party starts at 8:30, I mean you should leave home at 8:30 or start getting ready at 8:30. It is open for negotiation. Its funny right? Have you ever been to a strictly Nigerian wedding that started promptly? Actually, I have. My older sisters church wedding started promptly because my father is big on punctuality. Punctuality at many Nigerian celebrations is non-existent. Growing up, my dad made us resume boarding school as early as 8am while our friends resumed as late as 8pm. It was not a great feeling but it has imbibed the spirit of punctuality in me. If I'm meeting up with someone I'm always punctual but if someone is meeting up with me, its permissible to be extremely late because I get it. Just be upfront that you are running late so I don't get irritated.
Why are some cultures Monochronic and other Polychronic? An important factor is the predominant way of living in these cultures. In Polychronic cultures, the agricultural way of life is a factor because everything depends on the climate that can't be controlled by man. Time is slow because it follows the patterns of the seasons. In Polychromic culture, life is industrialized; everything is controlled and planned by man and success is determined by speed. The contrast is apparent.
Some writers also attribute the reasons for the difference in culture as a result of the weather. The further north you go in Europe the more time is perceived as important especially in Scandinavian countries. As you go south, time becomes less important. This may be because if you run late for a meeting the person may freeze to death waiting for you or it's dangerous to leave someone out since night falls quicker. While at the other end, the weather is warm and nice; there are long hours of daylight. However, there is no significant research to state for sure these are the reasons but it definitely is a contributing factor.
My point is everyone has to learn how to be culturally sensitive. Because someone is late to something doesn't mean they don't respect you, they lack manners or they are wrong. Its just culture. We are have to learn how to accommodate people, teach them respectfully that time is money in America so you have to be early to social meetings and vice versa.
Information was gotten from personal experience and graduate level communication classes.