There are friendship which are not totally true
The most hurtful truth in terms of friendship from your workplace is you used to think that your friendship from your workmates is true. You spent your years from them with laughter but after you decided to resign but you were still trying to reach your so-called "true" friends through mobile text, emails, Facebook and what not, but they didn't respond. When you checked their walls in FB, they were having fun at one another but none of them didn't care at you anymore. When you were on the company, they were so eager to hear your stories.
Yes, I had one close friend who is now my ex-friend who used to know my life story. She always wanted to be with me. After I resigned, she didn't communicate at me anymore. Take note, she was not the reason why I resigned. I didn't know why she became like that. Our bosses are busier than her so I don't believe that she doesn't have time. I also saw her wall in FB. I also saw that she's sometimes online.
My two years with her with good times was a big lie. Good thing that I had few true friends who never forget me in my previous company.