We present a comprehensive investigation of the Mg II k&h lines profiles under quiet solar conditions, as seen by IRIS. An in depth analysis of the various profile characteristics is provided, considering datasets covering diverse surrounding large scale magnetic configurations and different local activity levels, from pure quiet sun to regions underlying coronal holes or located under the active region canopy. The line profile characteristics are identified, the differences between Network and Inter-network regimes are characterized and the evolution of similar activity conditions is discussed. The statistical properties of the different activity levels are explored and the correlations between the different computed parameters are evaluated. Overall, the Inter-network regime is dominated by signatures of convective motions, which become suppressed in the Network, where the magnetic field leads to enhanced emission.