To me the most interesting thing about the Colonial Period is how the attitude in the colonies began to change. We moved from taking our connection to England for granted to becoming a country different from any other.
In speaking about the broadest sense of "the colonial period," I would have to say that the most interesting element had to be the sheer display of power is what strikes me about the colonial period. This was a time period in which might made right. The nations like Great Britain were "Great" because they were able to go out and overtake other nations. Power was constructed in the most liberal manner of appropriation. There was little regard for other nations in this process. It was either colonize or perish trying. This was a sheer and awesome display of power and it was sanctioned by nations. There was no one suggesting that it needed to stop. Spain, England, France were all seeking to control and to dominate. They did so through displays of power that obliterated anyone or anything that stood in its way. I would have to say that since the question is talking about "the colonial period," as a broad concept, I find it interesting that this massive display of power helped to construct reality as it is seen today. Certainly, the display of power can be criticized today. However, the reality is that the power of nations that colonized was and still is something actively sought out by nations both then and now, reflecting that one of the most abhorrent practices is still something seen today. I find that interesting.