Because, Tokyo has a unique look that makes it different from any other city in the world. The city turns into an epicenter for paper lanterns and large neon lights. Japanese men and women like to have a nice night out after a hard day of work. Tokyo turns into one of the wildest cities in all of the world, as there are constantly people everywhere and nobody seems to sleep. Districts known for their entertainment are ridiculously crowded, no matter at what time of day or night it is. Many shops and clubs stay open until 5 AM, when the subways first start running the next day. Tokyo has everything, no matter what you are searching for. Jazz shows, reggae shows, rock shows, dance clubs, gay bars, sex shows and anything else you can think of.
Though Tokyo's nightlife is wild and crazy, there is no place one can consider "the place to be" over other spots. Hotspots of the night are all over the city, varying in their price range, workers and most importantly, their atmosphere. Famous spots include Roppongi and Ginza, Kabuki-cho found in Shinjuku. A good way to start the night off is to just walk around the town, taking a look at the neighborhoods and just taking it all in. The atmosphere is unlike any other city. The streets will be overflowing with people and the neon lights will blind your eyes, but there are plenty of surprises to keep an eye out for.
There are plenty of bars, clubs and discos filled with male and female Japanese teenagers. However, for the older Japanese, the nightlife mainly attracts men. On the expensive end of the nightlife for older males are geisha bars, where talented women entertain crowds by singing, playing traditional Japanese musical instruments and just talking to the visitors. These kinds of places are found mainly in Kyoto and are usually closed to foreigners. They also are ridiculously expensive. The only way a foreigner might find a way in is by being invited by someone that should be there.
There are also many hostess bars. A woman will essentially boost your ego, as she sits with you, talks, listens to your problems and gives you drinks. This can be costly however as you will be the one buying her drinks. Hostess bars have been around in Japan for centuries, but a foreigner might not find it worthwhile, as the hostess usually can only speak Japanese. It is a way to get away from the troubles of work and family though, so they are quite popular.
The most popular place to see Japanese nightlife however is in the drinking bars, where most people go for a fun evening out. Many bars even have themes, such as Western-style and Japanese-style watering holes. Dance clubs as well as places to see live music are also very popular with young Tokyo teens. There are also relatively cheap restaurants that are quite good to eat out spread across throughout the city.