  We investigate the negative modes about Coleman-De Luccia bounces governing
vacuum transitions in de Sitter space, with the goal of gaining physical
insight into the various anomalous results associated with these that have been
reported in the literature. For the case of bounces with radii much less that
the horizon distance $H^{-1}$ we find two distinct regimes, distinguished by
the magnitude of the bubble nucleation rate $\Gamma$. If $\Gamma/H^4 \gg 1$,
then the behavior of the modes contributing to the determinant factors in
$\Gamma$ is much as in flat spacetime, and the calculation of $\Gamma$ goes
over smoothly to the flat spacetime calculation as the gravitational coupling
is taken to zero. This is not the case if $\Gamma/H^4 \ll 1$. These two regimes
correspond to the two possible outcomes of de Sitter vacuum decay --- either a
rapidly completed transition or non-percolation and eternal inflation. For
bounces with radii comparable to the horizon length, we confirm previous
results concerning anomalous negative modes with support on the bounce wall. We
also find further evidence supporting previous claims, based on thin-wall
arguments, of the absence of expected negative modes for a class of bounces
that arises when the initial and final vacua are nearly degenerate.
