Re: Rinse and repeat
They said that it could not be done.
He laughed, and said he knew it.
And when he tried that thing that couldn't be done,
he found he couldn't do it!
....
On the one hand, yes there are plenty of cases where "can't be done" is just conservative* laziness. On the other hand, sometimes it is genuinely not possible. The key skill is pushing hard enough to get past the first, but not digging in to ruin yourself against the second!
*Warning: this word is not being used in a political context. I shouldn't have to point that out but suspect I need to!