[bamboozled]

It's because people in Tokyo often participate in work or work related activities in their free time.

Many "perks" are provided by companies, this includes dinners, drinks tax breaks on your company housing etc.

The vast majority of people who are employed in Japan are also part of a family, which is their company. Your company even sends you for health checkups and they know the results of said checkups. If you're overweight, they'll make you go lose it etc.

Even peoples managers or the companies president will come speak at an employees wedding.

It's a totally different culture.