This review is devoted to the theoretical description and laboratory modeling of quasi-two-dimensional shear flows (including flows in thin layers of liquid and in rotating systems). Such flows are of interest in connection with the possibility of the appearance of ordered vortex structures in them as a result of the shear instability. The main attention is devoted to theoretical models in which the friction of the liquid against the underlying surface is taken into account. Comparing the theoretical results with laboratory data shows that friction plays the decisive role in the appearance and evolution of vortex structures. As an application, the large-scale dynamics of the earth's atmosphere is studied.