Euphemisms tend to arise for two reasons. First is because of our discomfort with physical realities, for example, body parts or death. For example, we refer to the white and dark meat in turkey and chicken because, probably in the Victorian era, we wanted to avoid referring to breasts or legs. We call the cessation of life "passing" because we don't want to say the word "death." We go to the ladies' room and the mens' room because we cannot bring ourselves to refer to what we will do there. In fact, even "bathroom" is a euphemism, since we are quite often not visiting there to take a bath. A second reason we create euphemisms is political. How we name our ideas and actions affects how palatable or distasteful they will be. Candidates and leaders all over the world are aware of this. Do we want "end of life counseling" or "death panels"? The euphemism chosen is capable of affecting the outcome of a proposal.
I have included three links for you, the first a rather famous Orwell essay that speaks to the political nature of euphemism, the second an article on euphemisms that have arisen as a result of the war in Iraq, and a third that is an interview with the author of a recent book on euphemisms, Euphemania: Our Love Affair with Euphemisms, by Ralph Keyes. I think all three should be useful.