like a red rag to a bull

”like a red rag to a bull”
to be certain to produce an angry or violent reaction
آنچه که به یقین باعث خشم گردد.

Example 1: It was like a red rag to a bull when Samantha heard John say that men should be paid more than women.
Example 2: For Claire, the suggestion of a women-only committee was like a red rag to a bull.