  There are certain families of words and word sequences (words in the
generators of a two-generator group) that arise frequently in the
Teichm{\"u}ller theory of hyperbolic three-manifolds and Kleinian and Fuchsian
groups and in the discreteness problem for two generator matrix groups. We
survey some of the families of such words and sequences: the semigroup of so
called {\sl good} words of Gehring-Martin, the so called {\sl killer} words of
Gabai-Meyerhoff-NThurston, the Farey words of Keen-Series and Minsky, the
discreteness-algorithm Fibonacci sequences of Gilman-Jiang and {\sl parabolic
dust} words. We survey connections between the families and establish a new
connection between good words and Farey words.
