(じゅうばこ)(すみ)をつつく

じゅうばこのすみをつつく
expression
to nitpick; to split hairs; to find fault with trivial details
1. to nitpick; to split hairs; to find fault with trivial details
To obsessively point out minor, insignificant flaws or details. Used critically of someone who focuses on trivialities instead of the big picture.
重箱(じゅうばこ)(すみ)をつつくような指摘(してき)はやめてくれ。
Stop making such nitpicky criticisms.
(かれ)はいつも重箱(じゅうばこ)(すみ)をつつくので、会議(かいぎ)(なが)くなる。
He always nitpicks, so meetings drag on.
全体(ぜんたい)出来(でき)はいいのに、重箱(じゅうばこ)(すみ)をつつくような批判(ひはん)ばかりされて(くや)しい。
The overall work is good, but it's frustrating to receive nothing but nitpicking criticism.

FORMATION:
重箱(じゅうばこ) (tiered lacquer box used for food) + の + (すみ) (corner) + を + つつく (to poke). Literally "to poke at the corners of a tiered box" — picking at the tiny bits of food stuck in the corners.

USAGE:
Almost always used critically. The phrase 重箱(じゅうばこ)(すみ)をつつくような is a common modifier for words like 指摘(してき) (criticism), 質問(しつもん) (question), or 議論(ぎろん) (argument).

VARIATION:
Also seen as 重箱(じゅうばこ)(すみ)をほじくる (using ほじくる "to dig out" instead of つつく).