  Rotation and mass loss are crucially interlinked properties of massive stars,
strongly affecting their evolution and ultimate fate. Massive stars rotating
near their breakup limit shed mass centrifugally, creating Be stars with
circumstellar disks and possibly driving outbursts. Using the MESA stellar
evolution code, we examine the effects of efficient angular momentum transport
on the main sequence and post-main sequence rotational evolution of massive
stars. In rapid rotators, angular momentum transported from the contracting
core to the expanding envelope can spin up the surface layers past the breakup
rate, particularly for stars near (or beyond) the end of the main sequence and
in low-metallicity environments. We also demonstrate that centrifugal
instabilities could arise in rapidly rotating massive stars, potentially
triggering the S Doradus outbursts observed in luminous blue variable stars.
Prior mass accretion from a binary companion increases both the likelihood and
the intensity of centrifugal mass loss. We discuss implications for massive
stellar evolution, Be stars, and luminous blue variables.
