Probably the last meet up

When I first started my career 4 years back, I met a bunch of people who became my kakis for the next 2 years. They were the ones who seen me cry and stressed up, and my pillar of support whenever I was demotivated at work. As time passes, they start to leave and pursue other stuffs. From a group of 7, I was the only one still in the firm now. They have moved on to other countries/careers or simply stayed home and be tai tai. A sad thing? To a certain degree, yes. But I guess I have somehow come to terms with people coming and going. It takes effort to refind a group of kakis and build up the relationships. But life is just like that isn't it? People come into your life and someday they leave. I didn't exactly enjoy today mainly because I was very tired and didn't feel very chatty. But I did realise some things today.
1) How impermanent the close relationships were. It makes me wonder sometimes whether the closeness was really there initially, or was it just because of work whereby you see each other everyday and so you feel close?
2) How selfish and self-centred I am. I didn't seem exactly interested in someone getting pregnant, or the 6 month old brought along by another. Or is it merely because of a different life stage we are going through that I find it hard to relate to?
3) How truly anti-social I can be. I sat at the table for around 2.5 hours and I spoke like less than 10 sentences. It makes me wonder why at times I can be such a social creature and being the live wire among the jc gang. On my journey home with one of them, we actually didn't spoke for more than 15 minutes. Feels weird hor considering people find me a talkative and chatty person. It reminds me that I am indeed anti-social by nature.
4) Why do people meet up and chat for hours? What is the purpose? I used to find that very entertaining and part of my social life. But now, I seem to find it no-need-to-be-done. We meet to gossip about people, complain about work and go home. What is the aim? To be updated about each other's lives? To physically see each other? What?
5) Why am I so unlike everyone who finds it really fun to watch movies and shop? Or am I jsut too tired today?
Maybe I'm thinking too much. After trying to figure out what happened in The Dark Knight.