Funny thing — every time I quote Shakespeare in casual conversation, people expect 'Et tu, Brute?'. It's true: that line from 'Julius Caesar' is the one everyone knows, uttered by Caesar as he realizes Brutus has joined the conspirators. But the play is a treasure chest of other zingers that keep coming back in movies, speeches, and memes.
I also love 'Beware the Ides of March' — the soothsayer's warning that haunts Caesar. Then there's Antony's show-stopping opener, 'Friends, Romans, countrymen, lend me your ears', which is basically a masterclass in persuasion. Cassius gives us philosophical bites like 'The fault, dear Brutus, is not in our stars, But in ourselves, that we are underlings', and he also sneers with 'Yond Cassius has a lean and hungry look.' For bravado and dread, you get 'Cowards die many times before their deaths; The valiant never taste of death but once.'
Other favorites I find myself dropping into conversation: 'It was Greek to me' for something incomprehensible, 'This was the noblest Roman of them all' as a bittersweet tribute, and Antony's bitter resolve, 'Cry Havoc and let slip the dogs of war' when chaos is unleashed. Even little lines about tears and loyalty like 'When that the poor have cried, Caesar hath wept' add texture. If you want to see these delivered, watch stage performances or the film versions — the cadence totally changes the meaning. I love revisiting scenes and imagining how actors put their spin on each phrase.