At first glance, this expression doesn’t seem so bad:
刺身のつま (sashimi no tsuma: (1) sashimi garnish; (2) something of no significance; something that can easily be done without)
Perceptions change when one learns what this つま really means; its kanji is the character for “wife”:
刺身の妻 sashimi + meat, flesh + wife
So a wife is either a “garnish” (that is, a way to beautify the real thing of substance—the fish/man) or “something that can easily be done without.” An expression this sexist is something I can easily do without!
