It is challenging if you are not the chosen/favoured ones. I know a new joiner getting B for first full appraisal, where the RO had to write long statement to justify. But for me, first 3 years RO can tell me i still new and a C grade is normal. 4th yr C+ she say very good liao, very few get B. 5th year back to C grade and she says she will fight for better projects for me next yr (i.e. 2020). Waiting to see what cock reason she will give for my 6th appraisal in a few days.