Very similar to the phenomenon where someone types qwertyuiopasdfghjklzxcvbnmmnbvcxzlkjhgfdsapoiuytrewq but the person is so bored they decide that maybe they should press all the keys twice in quick succession.
wow... I already typed qwertyuiopasdfghjklzxcvbnm, qqwweerrttyyuuiiooppaassddffgghhjjkkllzzxxccvvbbnnmm and qwertyuiopasdfghjklzxcvbnmmnbvcxzlkjhgfdsapoiuytrewq! well time to find another way to type it...
qqwweerrttyyuuiiooppaassddffgghhjjkkllzzxxccvvbbnnmmmmnnbbvvccxxzzllkkjjhhggffddssaappooiiuuyyttrreewwqq!