In this adventure as a dad  set out to  bring home  one leaf from  a tree in Peter’s Park.  Introducing  myself to strangers, my daughter and I asked MBTA riders seated beside us 1)  their destination, and 2) one thing on their mind or heart .     Emad left his  nineteen-month-old  and rode the orange line to Northeastern University where he is  teaching 20 percent and researching   80 percent of the time .   Esther, on the way to the dentist wore  black lipstick,  a black leather  top open at the chest  and white midriff . T he  Army  veteran of a foreign war  had been thinking of the state of the world as she rode the escalator from the station.   A fter  a  tour of  three-and-a-half year s ,  Esther  had gained  a septum nose  piercing and  dragon neck tattoo.  “I’m a veteran and   looking for a career , ” she sa...