Although,
technically "could" is the past tense of "can", so maybe they're emphasising their past ability to care, in contrast to the present.
(, Wed 1 Oct 2008, 19:39, Reply)
I think you are missing the point Sir Cleese is making.
It is the lack of "not" that matters.
(
Redsushi! Whoop! Whoop! Yes, that one!, Thu 2 Oct 2008, 0:49,
Reply)
No I'm not
It's like if someone says "do you have a good job" and you say "I did". "Did" being the past tense of "do" - thus emphasing the lack of having a good job in the present tense. Since "could" is the past tense of "can", as well as the conditional present (or something), then this could be what Americans mean.
(, Thu 2 Oct 2008, 19:34, Reply)