What does "I kiss my sense of social belonging goodbye" mean?

What does this sentence mean?

Living here, I kiss my sense of social belonging goodbye.

This quote is from David Mitchell's essay about his life in Japan.

As far as I understand it means something like he was enjoying his isolated life in Japan but I'm not really sure.

Well, we say goodbye to something when it is going, so it means that he used to have a sense of social belonging, but he no longer did when living in Japan.

As far as I understand it means something like he was enjoying his isolated life in Japan

It doesn't really tell us much about whether he saw this state as enjoyable, unpleasant, or had mixed feelings about it. "To kiss something goodbye" has become a set phrase (a bit of a cliché really, meaning no disrespect to Mitchell, whose writing I enjoy) that doesn't on its own say whether we are happy or sad to be done with it; we can kiss our sorrows goodbye and our hopes.

It would lean slightly toward saying he found it unpleasant (we literally kiss our friends goodbye more often than our enemies, after all), but only very slightly so that he then goes on to describe this as enjoyable is not contradictory.

Japan, he says, does not fully welcome foreigners into its society. Hence, he does not belong there as he had belonged to his native country, and so he must "say goodbye" to that feeling of belonging. He feels like an outsider now.