Flip (one's) lid British informal slang
React to something very strongly, as with anger, excitement, or surprise
As soon as my mom knew that I had passed the university entrance exam, she totally flipped her lid.
His parents will definitely flip their lid once they find out that their son dropped out of school.
The verb "flip" should be conjugated according to its tense.
This slang, with their allusion to losing the top of one's head, dates from the 1930s and 1940s.
people often do irrational or foolish things when they are in love.
I and my boyfriend have decided to get married in the summer. I don't think that's wise, since we won't have enough money saved by then to set up house. But then, one cannot love and be wise.