When we were taught this history at school we were all informed of the negative aspects of our empire. Yes, he enslaved people, yes we conquered whole nations, yes we wre the big boys on the world playground at one point. However, no nation ever just goes to other countries and does those things for the fun of it. Everything that was done had, then, legitimate reasons for it. At them time, Britan was one of the many European nations competing for dominance in the world. We had been fighting amongst ourselves for centuries but with the discovery of the Americas and other places, new opportunities came about. Opportunities for land, wealth, resources, everything we would need to keep competing with the rest of Europe.
So to summarise, our Empire was not the result f some British ideal of superiority but rather a consequence of our need to stay ahead of our immediate neighbours.
If anyone disagrees please let me know.
P.S. Just incase you misinterpret my words, I DO NOT endorse the conquest or enslavement of other people. Just so you know.