To explain why I am so uncomfortable with "I can't use it for more than X" anecdotes: My grandma couldn't do more than automatically playing DVD on her windows

To explain why I am so uncomfortable with "I can't use it for more than X" anecdotes: My grandma couldn't do more than automatically playing DVD on her windows desktop. My wife can't do more than opening and closing the door on any random semi-truck. I can't do more than make horrible sounds on a violin. All of these are only half of the story, and the receiver of the message is supposed to guess the other half perhaps ? But of course, which is the other half ? Is there a point to be made about any of these or is it just a random observation ? Basically it brings more questions that it answers.