Madness (Feigned and Real):

. . . So help you mercy,
How strange or odd so e'er I bear myself--
As I perchance hereafter shall think meet
To put an antic disposition on--
That you, at such time seeing m, never shall,
With arms encumbered thus, or this head-shake,
Or by pronouncing of some doubtful phrase,
As 'Well, we know', or 'We could and if we would'.
Or 'If we list to speak', or 'There be and if there might',
Or such ambiguous giving out, to note
That you know aught of me--this do swear,
So grace and mercy at your most need help you. (Hamlet)

My lord, as I was sewing in my chamber,
Lord Hamlet with his doublet all unbraced,
No hat upon his head, his stockings fouled,
Ungartered and down gyved to his ankle,
Pale as his shirt, his knees knocking each other,
And with a look so piteous in purport
As if he had been loosed out of hell
To speak of horrors, he comes before me. (Ophelia)

"I am but mad north-north-west.  When the wind is southerly, I know a hawk from a
handsaw." (Hamlet)

"They say the owl was a baker's daughter.  Lord, we know what we are, but know not what we
may be . . .I hope all will be well.  We must be patient.  But I cannot choose but weep. . ." (Ophelia)