Consumption satisfaction depends on other factors apart from the inherent characteristic of commodities. Among them, positional concerns are central in behavioural economics. Individuals enjoy returns from the ranking occupied by the consumed item. In public good, agents obtain satisfaction from their relative contribution. We analyse how positional preferences for voluntary contribution to a public good favour players' contributions and could lead to social welfare improvements. A two-player public good game is analysed, first a one-shot game and later a simple dynamic game with inertia. Homogeneous and non-homogeneous individuals are considered and particular attention is given to the transition path.