Love is blind
This was coined by Shakespeare and was quite a favourite line of his. It appears in several of his plays, including Two Gentlemen of Verona, Henry V and The Merchant Of Venice; for example, this piece from The Merchant Of Venice, 1596:
JESSICA: Here, catch this casket; it is worth the pains.
I am glad 'tis night, you do not look on me,
For I am much ashamed of my exchange:
But love is blind and lovers cannot see
The pretty follies that themselves commit;
For if they could, Cupid himself would blush
To see me thus transformed to a boy.
Modern-day research supports the view that the blindness of love is not just a figurative matter. A research study in 2004 by University College London found that feelings of love suppressed the activity of the areas of the brain that control critical thought.
See other phrases and sayings from Shakespeare.
See also: the List of Proverbs.