Quoting Bill the Bard like everyone else

Twelfth Night

This fellow is wise enough to play the fool;
And to do that well craves a kind of wit:
He must observe their mood on whom he jests,
The quality of persons, and the time,
And, like the haggard, cheque at every feather
That comes before his eye. This is a practise
As full of labour as a wise man's art
For folly that he wisely shows is fit;
But wise men, folly-fall'n, quite taint their wit.

--Viola, Act III, scene i

Quoting Bill the Bard like everyone else

Twelfth Night

This fellow is wise enough to play the fool;
And to do that well craves a kind of wit:
He must observe their mood on whom he jests,
The quality of persons, and the time,
And, like the haggard, cheque at every feather
That comes before his eye. This is a practise
As full of labour as a wise man's art
For folly that he wisely shows is fit;
But wise men, folly-fall'n, quite taint their wit.

--Viola, Act III, scene i