From Longman Dictionary of Contemporary Englishof all people/things/places etcof all people/things/places etcused to emphasize that your statement is true of one particular person, thing, or place more than any other You shouldn’t have done it. You of all people should know that. She did not want to quarrel with Maria today, of all days. → all
Examples from the Corpus
of all people/things/places etc• A kitten, of all things.• There I was admitted by the butler, of all people.• William Forsyth began it before he sold out, with the help of John Brown, of all people.• She heard, of all things, a piano.• So, in Missouri, of all places, my Koreanization began.• She was a homeless wanderer until tiny Delos alone of all places on earth consented to receive her.• He of all people picks his words carefully.• The rest of my offences were committed in self-defence, when I found the hands of all People were against me. 