You are Gabby the taxi cab. You are trying to make a living so get your customers to their destinations on time (if not early). They happier they are, the bigger the tips.
GabCab is a time management game. You are a taxi cab and you are trying to transport customers to their destinations. Try to get them there on time or, even better, early to gain better tips. Use the money you make to upgrade your taxi to make is faster, ride smother, etc. to get even better tips. Watch your fuel gauge and, if needed, plan a stop at the Gas Station so as to not run out of fuel.