Oblivion (oh-bliv-éon) — A person who is so oblivious to his or her surroundings that they abandon all common courtesy and commit daily acts of rudeness. Oblivions are oblivious to the very fact that they are Oblivions, which makes it difficult for an Oblivion to ever see the error in his or her ways.
For example: A line of courteous people will form at the Starbucks coffee counter, with each person ordering in their turn. An Oblivion usually stands to the side of the line, staring so intently at the Frappuccino menu that when a clerk asks who's next, they are awakened out of their Oblivion trance and will yell out their order, cutting the line as if there weren't a line at all. They're also parked in a no-parking or handicapped zone.
Another example is the movie theater Oblivion, who arrives to a packed theater with an Oblivion friend, after the movie begins. Together they will search for seats and eventually spot two separate, empty seats in the same row. They will then proceed to ask the people who bothered to show up early so they could choose the seats they wanted (non-Oblivions) and ask everybody in the row to scoot down a seat so they can sit together