He wanted to make it quite known that I wasn't qualified to work in the industry (even though I worked for him in the industry just fine for several years and I was the one leaving the job on my own accord?) and that I wouldn't be able to find another job without a degree. Even though I deep down knew everything he was saying was not really based in any reality, the things he said were actually pretty hurtful at the time.

I had no trouble walking into another job that provided far more interesting work, and paid considerably more, for people who showed a much greater appreciation for us to be able to work together. I still don't know what the purpose of that email was. Sad to see me go, I guess?