That's a really interesting point. So maybe we're likely to comment on something positive that far exceeds the normal experience, but not say anything where "good" is already expected. I'd never thought of it like that.
In my job, my boss expects everything to be fantstic, for him 'good' simply won't do and he tells me so every day, but occasionally you have to push something which is merely 'good'.
It can be a downer, but when I do 'fantastic' I know I've deserved the praise which is a massive moral boost.