At your old job, you were probably smashing it. You knew all the people, you knew all the systems. You knew the history behind how decisions were made, and you knew how to get things done. You might've even been the resident expert on some critical thing, and there was always a queue of people waiting for your help. You were part of a team, and you felt like you belonged there - you didn't need to impress anyone. We probably hired you because you were performing at such a high level at your previous job.