From "passed away" to "Chilean sea bass," euphemisms are a way to avoid unpleasant terms or phrases.
But in Euphemania, Ralph Keyes argues that using them isn’t necessarily lazy or evasive; it can actually be harder to not say what we mean and still get our point across.
http://www.npr.org/2010/12/14/132056878/-euphemania-our-passion-for-not-saying-it