On a global scale, the US and Canada have a lot in common, with large overlaps in history, culture, religion, language and politics.

However, there are also differences. For example, Canadians are often described as having a bigger trust in government, a more liberal lean (Canadian politics have for a long time been dominated by the liberal party), being less individualistic and being less religious than their US counterparts. Most people can probably list some cultural aspects that they think differ between the countries, which might not have been the case in the 17th century.

When and why did the cultures of the colonists start to diverge?

Note: I don't want this to turn into a debate as to what the actual differences are, the questions concerns the major causes of said differences.