During appraisal, they will deny promotion saying you didn't meet the expectation, you don't have leadership qualities, and you had several drawbacks in our objective/goal.
During resignation, they will say you are the core member of team; you are the vision of the company how can you go, you have to take the project in shoulder and lead your juniors to success.
Trainee: "Yes boss enough, now I understood my future. For an appraisal I will have to resign ... !!!"