I try to be civil/nice most of the time, as it is usually the best way to minimize unpleasant, stressful situations. Once in a while it just doesn't work, and then I sometimes do drop the Miss Nice mode, and express myself bluntly. Fortunately though, the civil mode is usually the best path. 
_________________
If a man does not keep pace with his companions, perhaps it is because he hears a different drummer.
Let him step to the music which he hears, however measured, or far away.--Henry David Thoreau