  I provide some simple physical arguments that, once gravitation and some
subtleties are taken into account, rather broad classes of potentials result in
instantons which tunnel relatively rapidly between perturbatively stable
minima. In particular, due to some previously unappreciated technical
subtleties, the decay rates for instantons which may be well-described as
thin-wall are much larger than the usual Coleman-de Luccia result. I discuss
with some level of rigor when the thin-wall approximation holds and clarify
some misconceptions regarding the application of this approximation and its
meaning. I also point out potentials involving small differences between the
maxima and minima generically decay relatively rapidly. These two classes of
potentials include those usually used to argue for the existence of a string
landscape and in light of these results it is not clear that de Sitter vacua
presently understood will generically be cosmologically long-lived.
