Parents who say "I did my best" are usually just unreliable narcissists who expect credit for doing the bare minimum

My parents did their best, and no, they were not narcissists. what more can anyone do but their best? Is there something more than the best? Of course, we children used that phrase "they did the best they could" do not remember mom and dad saying that.
I think ungrateful children sometimes want what parents can't provide in terms of extras and feel neglected if they don't get their way all the time.