I lived in Tokyo for a year and my favorite hobby was taking the train somewhere about 10 miles from home then just wandering around, vaguely towards home. It's such a beautiful walkable city, and the safety means you don't need to worry about much at all. I usually walked at night and I would come across drunk people stumbling home, pets (and rodents!) roaming the streets, construction in the middle of the night, strange open late restaurants / bars, and all kinds of other things. Living in Japan has its downsides but that activity was a nice reminder of what a cool place it is. I continue going back every year just to explore new little places I've never gone. I recommend anyone who visits to find some time to just wander around. Pick a destination and walk there and see what you find.