The phrase "the cat’s crack", meaning "the height of excellence", was first coined in jest during a family conversation about the low-riding waistline of one family members pants, Catherine(a.k.a- Cat) in Northern New Jersey on April 15, 2018. It can be used interchangeably with the phrase “the bee’s knees” that first became popular in the U.S. in the 1920s, along with "the cat's whiskers" (possibly from the use of these in radio crystal sets), "the cat's pajamas" (pajamas were still new enough to be daring), and similar phrases that didn't endure: "the eel's ankle", ...
To make a complete mess of something, to fail miserably to achieve your objectives.
WIFE: Did the furniture arrive from IKEA last night?
HUSBAND: Yes.
WIFE: Was my fold-away bed couch with built-in foot spa there?
HUSBAND: Yes.
WIFE: Ooooh!! Will you assemble it for me?
HUSBAND: I started on it last night, but I made a cat's crack of it.