  Studies of the superconducting proximity effect in normal
conductor/superconductor $(N/S)$ junctions almost universally assume no
effective electron-electron coupling in the $N$ region. While such an
approximation leads to a simple description of the proximity effect, it is
unclear how it could be rigorously justified. We reveal a much more complex
picture of the proximity effect in $N/S$ bilayers, where $S$ is a clean s-wave
BCS superconductor and $N$ is a simple metal with a repulsive effective
electron coupling. We elucidate the proximity effect behavior using a highly
accurate method to self-consistently solve the Bogoliubov-deGennes equations.
We present our results for a wide range of values of the interface scattering,
the Fermi wave vector mismatch, the temperature, and the ratio $g$ of the
effective interaction strengths in the $N$ and $S$ region. We find that the
repulsive interaction, represented by a negative $g$, strongly alters the
signatures of the proximity effect as can be seen in the spatial dependence of
the Cooper pair amplitude and the pair potential, as well as in the local
density of states near the interface.
