The physics of the bistability and relevant phenomena in sinectic C* liquid crystals has been discussed. The problem is treated in terms of the director and not of its projection onto the smectic plane (the so-called c-dircetor). As in the case of nematic liquid crystals, two anchoring energies are considered to be important, the zenithal and the azimuthal ones, both arc unpolar. This allows the derivation. of a new, basic criterion for the bistability of the director switching in the ferroelectric cells without alignment layers or with. strongly conductive alignment layers. In the case of weakly conductive alignment layers, an additional criterion has been found that originates from the internal field in a liquid crystal cell opposite to the external field. This field can cause monostable director switching or an inverse bistability. It is also responsible for the hysteresis-free switching and the electrooptical V-shape effect in the smectic C* phase.