In this thesis, the properties of ferroelectric domains and domain walls in Pb(Zr0.2Ti0.8)O3 are studied in three research avenues using piezoresponse force microscopy. In the first, the switching dynamics are investigated in the context of crackling physics. The importance of establishing the dynamical regime of domain wall motion at which the system is driven is revealed and tentative spatio-temporal correlations of switching event in the creep regimes recently predicted theoretically are observed. In the second, correlations are studied between the magnitude of domain wall currents and geometrical distortions of the walls, which are both affected by the defect density. These results suggest that the defects affecting the conduction do not predominantly lead to simultaneous distortions of the domain wall as seen from the film surface. In the third, polarization rotations at the crossings of ferroelastic twin domains with enhanced sensitivity to external mechanical force are uncovered.