I'm not wholly sure I see what you mean. Humans are, by nature tribal, & ways will be found to resist homogenisation of culture - examples of this can be seen e.g. in support for football teams etc. Common ideals/idea etc can make things boring - it is, after all the ability to have an opinion that makes us human (a bit more common understanding would also be a good thing, although the longer I live here, the less I understand the English)

I would disagree with your example of colonial expansion - our was driven by three things:
1) Trade (esp. with N America/India)
2) The protection of same - witness the conquest of India, which started in three small area, & spread as the neigbours of these became a threat & were defeated & colonised in turn (or, as in the case of the Afghans, gave the army a bloody nose).
3) The opportunity to foil the French.

Andy