I've applied for an internal team transfer at work. I've interviewed with the new team and hiring manager and want to accept their offer.
My manager takes things very personally and I haven't worked for him very long. In my time working for him he has lost his cool and gotten into arguments with people. I'm quite shy and I'm worried about how he will react.
The main reason for moving is because I think he is unprofessional. He is new to management and only has two reports now - my coworker is also interviewing for a transfer. I think it looks bad on him so I can only imagine how he is going to receive the news.
What is the best way to tell him?