I (do) declare! old-fashioned expression informal
Used to express surprise.
A: Congratulations! You have passed the exam. B: Well, I declare!
Peter: Did you know that she gained promotion? Linda: I declare!
To be surprised by some sudden occurrence
To greatly surprise, shock, or confuse someone
Put an end to a bad experience or situation in an especially negative way, usually a series of unpleasant events
I argued with my wife this morning and failing in negotiating with my customer has put the tin lid on my bad day.