I wish I'd said that
An expression usually of admiration for another's cleverness or disappointment that one didn't say such a thing oneself. Oh man, that's a great comeback—I wish I'd said that! I wish I'd said that, but no, I stammered like an idiot instead.
I wish I'd said that.
a comment of praise or admiration for someone's clever remark. Mary: The weed of crime bears bitter fruit. Sue: I wish I'd said that. Mary: I wish I'd said it first. John: Tom is simply not able to see through the airy persiflage of Mary's prolix declamation. Jane: I wish I'd said that. John: I'm sorry I did.