Our picture of galaxy evolution currently assumes that galaxies spend their life on the star formation main sequence (SFMS) until they may eventually be quenched. However, recent observations show indications that the full picture might be more complicated. To investigate this matter, I trace galaxies across cosmic time in the high-resolution cosmological hydrodynamical Magneticum simulation and find that a consistent evolution scenario along the SFMS until today is in fact rare. Indeed, a formation shaped by rejuvenation cycles on giga-year time scales is much more likely with the SFMS to be regarded rather a snapshot of star formation activity than an evolution track. Consequently, I find that most active and a significant fraction of quenched galaxies at z=0 have experienced rejuvenation cycles. Such a rejuvenation can even occur passively in a Milky-Way-like fashion with a low but constant star formation rate as the SFMS itself declines over time. Finally, I use this more refined view on star formation histories not only to relate them to the rates and geometry of their gas flows and the agreement with the bathtub model, but also to show how different forms of rejuvenation cycles leave characteristic imprints on stellar masses, metallicities and ages of present-day galaxies, as well as their radial distributions. This could prove a helpful tool to deduce formation histories of nearby galaxies as well as to formulate expectations for observable tracers.