Not too long ago I changed jobs and it was a tough decision to make but I think I made the right move. I tried to leave on good terms with everyone as well as the company that I left. You never know when and where you might run into someone again. Well the other day I got a call from a former co-worker asking if I could do some side work for a friend of his. I reluctantly said sure, not knowing what I was getting into I am always reluctant, but I did not want to burn a bridge so I said I would take a look. Well long story short, the job took me about 30 minutes and I was able to get his friends business back on-line and that was worth a lot to him. I am sure I could have charged more but I think that $200 for spending 15 minutes on writing a purge script for his database was more than fair.
So just know that people you used to know may pop up out of the blue with a good opportunity for you.