To be or not to be · All that glitters · What's in a name · All the world's a stage · Et tu Brute
Misquotations — Money is the root of all evil (Bible, not Shakespeare). Alas, poor Yorick! I knew him well (actually: I knew him, Horatio). The lady doth protest too much now means complain but in Shakespeare means vow emphatically. Et tu, Brute? is from Julius Caesar, not from history.
Context matters — O brave new world, that has such people in it (The Tempest — Miranda has never left the island, so this is ironic, not celebratory). Brave new world is naive wonder, not optimism. Huxley uses this irony for his dystopian novel title.
All the world's a stage — From As You Like It, spoken by the melancholic Jaques. Lists seven ages of man from infant to second childhood (sans teeth, sans eyes, sans taste, sans everything). Jaques is a satirist — the speech is neither celebratory nor simply mournful but mordant.
Something is rotten — Not spoken by Hamlet but by Marcellus — the soldier, not the prince. Context: after the ghost appears. The line describes political corruption in Denmark. Often misattributed to Hamlet himself, which changes its register.