Confidence vs. Meanness

Does confidence come with meanness? Are they essentially one in the same? Why does it seem that people who are self confident are also rude, selfish and for lack of a more sophisticated term - mean? Even my ownself, who is described by others as sweet and too kind find that as I gain confidence at times, I loose my never-ending kindness. So my question is to be confident - does it come with other less negative qualities?