Person A is an Olympic-level athlete. He can perform amazing physical feats. The limits of his ability can be scored against some sort of metric (lap time, distance jumped, etc.), and since he's working to improve on them, his own personal limits are known to him.

Person B is of average physical fitness.

Person C has a moderate chronic illness. He struggles to perform basic physical feats, but can function independently with some difficulty.

If all three of these people were secretly transplanted into an environment with lower oxygen levels and began to experience mild hypoxia, it seems that Persons A and C would both be more sensitive to this change than Person B. Person A would notice it because he would no longer be able to perform outstanding physical feats to the level he's accustomed to. Person C would notice it because he'd struggle to carry out basic activities.

[Edit for clarity: I'm not saying that Person B would never notice this, but that he would be less sensitive to it, because his performance is higher-variance and subject to less of a "state change", and doesn't have a fine, frequently-scrutinised boundary between what he can and can't do.]

Alternatively:

Person D is a voracious infovore with high reading comprehension. She's used to grappling with precise language.

Person E is an average-level reader.

Person F has some sort of reading-related disability.

It seems that Persons D and F will be more sensitive to badly-punctuated writing than Person E. For example, Person D might be able to parse a sentence in two or three plausible ways, while Person F might not be able to parse the sentence at all.

Both of these cases involve both ends of an ability distribution being more sensitive to degradation of the environment than central cases. Are there better examples? Is this a phenomenon we actually see in the real world? If so, does it have a name?