I tried carrying a backpack last year when I was taking transit a lot. After a while I started locking it up in the lodge lockers. Just too much of a PITA unless you've got stuff you need on an ongoing basis ($1 each time you open the locker)
I told my kids, "Someday, you'll have kids of your own." One of them said, "So will you."
-- Rodney Dangerfield.