I think that the thing we should always have in our minds is cross cultural differences.
Just remember how many people are in SFI and from how many countries. The whole world on one place. Each of us has different background, customs, habits...
Nevertheless, you should always try to help your PSAs as their success is yours at the same time. But, if you think you have been rated poorly, you could ask him/her for the reason and try to find solution for your problem or misunderstanding.