Planetary Nebulae (PNe) are a consequence of stellar evolution, being interestingly linked with the parent stars and their environment. These objects have emission-line spectra with remarkable features, being, as such, versatile tools in astrophysics. PNe can reveal chemical features of Interstellar medium, being also used as distance indicators or to reconstruct the evolutionary history of the parent stars. The understanding of PNe is important for full exploitation of these and other possibilities; nonetheless, there are still some gaps in the knowledge of both the formation scenario and in the physical mechanisms, which should be filled in order to allow the proper use. In this colloquium, a new approach to physical mechanisms (specially shocks) and its impact on abundance calculations will be discussed. A connection between shocks and the morphology will be also shown. Novel results for two Type-I PNe are presented. Their morphological substructures seem to be a favorable environment to shocks, a result that renders a revision on abundances necessary. A larger sample of PNe with shocks diagnosed are under construction, as well as the analysis of other types of PNe.