Is my vision that bad? No, it's just a bug in Apple's Calculator

On mobile devices, Apple’s Calculator app has always been one of the most frustrating apps I’ve ever used, and I’m surprised it’s a stock app by the company itself. If you press buttons quickly, like you would a normal calculator, many of the key presses simply don’t register at all. I’m not sure if they’re prioritizing some pretty little visual animation over actual functionality, but it’s incredibly surprising from a company that focuses on user interaction, supposedly.

Apple's greatest weakness is that many of it's fans and I'd assume people in house assume they are the epitome of UI design when actually it's not. The thoughtlessness/pixel ratio might be worse than Microsoft in some cases, which can be hard to believe.