Since the fluid in the inner part of the boundary layer is slower, it is more greatly affected by the increasing pressure gradient.
For a large enough pressure increase, this fluid may slow to zero velocity or even become reversed causing a flow separation.
The more efficient mixing which occurs in a turbulent boundary layer transports kinetic energy from the edge of the boundary layer to the low-momentum flow at the solid surface, often preventing the separation that would occur for a laminar boundary layer under the same conditions.
This physical fact has led to a variety of schemes to actually produce turbulent boundary layers when boundary layer separation is dominant at high Reynolds numbers; the dimples on a golf ball, the fuzz on a tennis ball, or the seams on a baseball are good examples.
Aeroplane wings are often engineered with vortex generators on the upper surface to produce a turbulent boundary layer.