It's a fun experience just being in the absolutely packed rush hour Tokyo trains. Although I don't have to worry about claustrophobia since I'm 6'3 tall and I'm able to look out above the heads of everybody else.
Complaints aside, I love Tokyo's train and subway network! I can get around easily, with most places being no more than a 20-minute walk away from the nearest train/subway station, and many of the lines that connect central Tokyo to its neighbors have express routes that skip many stations along the way. Some lines even have special cars with reserved seats that cost extra. I sometimes take them whenever they are available; they make for a very comfortable ride.