Many fundamental theories of ocean dynamics involve a flat ocean bottom, which greatly simplifies derivations. But including a bottom slope or bottom roughness can yield profound differences. For example, with even a weak bottom slope, the traditional baroclinic modes shift to a set of orthogonal surface modes and bottom-intensified topographic waves. The same shift occurs with very modest bumps. Thus the traditional baroclinic modes, widely used in oceanography, are probably not dynamically relevant. This is in accord with current meter observations, which indicate a dominant mode which is surface-intensified and decays monotonically to the bottom. This mode, the first of the surface modes over topography, has a larger horizontal (deformation) scale than over a flat bottom; thus eddies should be 20-50% larger than predicted over a flat bottom and should propagate faster, as is observed. Bottom bumps also impact current stability, reducing the vertical transfer of momentum by baroclinic instability and favoring lateral transfers instead.