  We describe a family of words in Thompson's group F which present a challenge
to the question of finding canonical minimal length representatives, and which
show that F is not combable by geodesics. These words have the property that
there are only two possible suffixes of long lengths for geodesic paths to the
word from the identity; one is of the form $g^k$ and the other of the form
$g^{-k}$ where g is a generator of the group.
