rue the day
Verb
Meaning
rue the day (third-person singular simple present rues the day, present participle ruing the day, simple past and past participle rued the day)
(idiomatic) To seriously regret one's actions.
Examples
I want to say unequivocally the Queen is magnificent. She is the enduring force, she is the glue that makes everyone feel good. She is beloved. I would rue the day when she may not be here.
She has good instincts, but wrong judgments. She'll rue the day.
I believe we shall make them rue the day they try to invade our island. No such discussion can be permitted.
I'm sorry I ever met you" is effective enough, but how much more piquant is the same communication expressed as: "I rue the day I met you.
I just had my first child in February and I rue the day my son is this big!
Democrats will rue the day they demanded resign.