By just about any measure, the largest metropolitan area in the world is Tokyo. When you have over 30 million people living in a metro area, things get busy.
The busiest train station in the world by daily ridership is Tokyo’s Shinjuku Station. Every day over three million people pass through the station. Making your way through Shinjuku Station during peak hours is an intense experience, and one I highly recommend.
Tokyo is also home to the busiest pedestrian crossing in the world. Outside of the JR Shibuya Station is an x-shaped street crossing which just happens to be located in one of the busiest parts of the city. It’s common for several hundred people to be crossing this intersection at any given time. During peak commuter hours, I’m sure the crowds of crossing pedestrians number in the thousands.
Some of the smaller train stations have the most intense crushes of people, simply because their size can’t adequately handle the number of people flooding in and out. For instance, the JR Harajuku Station has hideous pedestrian traffic jams because hundreds and hundreds of people enter through a narrow tunnel.
I didn’t mind the crowds in Tokyo. The big exception was when actually riding on public transportation. It’s just no fun to be packed asses to elbows in a train.