How to keep your people happy

I am happy at work. I like my job and I do it decently well. It gives me opportunities to develop my skills and interact with intelligent and interesting people in an international environment - without even lesving the office.
Objectively speaking, not much has changed since three months ago, when I still did not kmow if I was going to be fired. I actually do pretty much the same things. But there is one major difference: I have something I am responsible for.
This is really important. It does not take very much either. I am responsible for a small node in a very big system, but it has to do with emergency calls, so if it does not work properly people can die.
You do not have to have responsibility ove life and death to feel good about what you do, though. Rather, it may be more comfortable if you dont. But if you can look back after each working day and say "this road would not be paved if it were not for me" then your work gets some meaning.
Without meaning in your work, you are just a cog on the gears of the huge machine, ready to be chewed up and spit out like the Chaplin character in Modern Times. Not very fulfilling, although some people evidently like it.
In Japan, the big companies used not to fire anyone. They had given you a lifetime employment. That does not mean they did not want yo get rid of people. So they placrd them by the window, did not give them any tasks, and did not invite them to any meetings. The last is especially important in a culture where participating and being a part of something defines you. Without relations, you do not exist in Japan. Without responsibility, nobody wants to talk to you. Those people quit after a while.
So the secret is responsibility and relations. With that, going to the office has meaning. Without it you might as well quit, before you get a tan on one side of your face by sitting next to the window.