Gena is a gearhead with a need for speed. She chose to become a cabbie because she finds it more interesting to weave through traffic than loop around a track.
Despite being a talented entertainer B.D. Joe has chosen to become a cabbie rather than attempt to perform professionally. He loves to make people's day and finds his work too enjoyable to give up.
When Gus was younger he was rowdy and obsessed with being the best. He pioneered the "crazy" style when he bought his 1955 Jalopy. As Gus got older his personality became more relaxed by learning the value of strategy through gambling.