Why can't he just be happy for me and wish me all the best?

I lost my current position at work and now looking for a new job. I don't want to stay where I'm not appreciated. I worked as a librarian in a public library and now applied for a scientific library. When I told my friend that, he told me that those people are going to change me. I asked why does he think that, and he only answered that I'll see. It didn't sound like encouragement that I can become a better person being around highly educated people. It sounded more as if he is accusing me of becoming a bad person. At the same time, he knows how bad I felt at my old job, and how mistreated I was. It sounded to me as if he is afraid he won't be good enough for me anymore.
Why can't he just be happy for me and wish me all the best?
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