The thing I've discovered, in the years since the nurse said that to me, is that there is a grain of truth in "You can if you make yourself." Just a grain. When people say things that really burn our biscuits, this is often the case. It's that grain of truth getting under our skin. Yes, it's faintly true that "you can if you make yourself." It will take an unbelievable amount of Herculean effort, and it will use up massive amounts of time where others can knock the chore out in a few minutes. But yes, ultimately you can. Just the same as a person with paralyzed legs CAN climb a hill by clawing to the top with the hands and fingers. Exhausting? Of course. And it would take forever, while a person whose legs work can just stroll on up.

This is why spouting that sentence off to someone right at the time when they're buried under the biggest pile of rocks is insensitive. And it's not what they need to hear just then.