Interviewers don't ask "what is a BAdI?" They ask what you did when it didn't trigger, why you chose that hook over the other three, and what happens to it at the next upgrade.
This 32-page PDF is built around those questions. Every one starts with a real project scenario, then gives you the question as an interviewer phrases it, a plain-language answer you can say out loud in about a minute, the trap that quietly exposes a memorised answer, and the follow-up that usually comes next.
What's inside — 30 questions in 6 blocks