Although there are many instances in editing where removal of redundancy improves clarity, the pure-logic ideal of "zero" redundancy is seldom maintained in human languages. Bill Bryson says, "Not all repetition is bad. It can be used for effect ..., or for clarity, or in deference to . 'OPEC countries', 'SALT talks' and 'HIV virus' are all technically redundant because the second word is already contained in the preceding abbreviation, but only the ultra-finicky would deplore them. Similarly, in 'Wipe that smile off your face' the last two words are tautological—there is no other place a smile could be—but the sentence would not stand without them."