"Love and reason keep little company together:" comment in reference to A Midsummer Night's Dream.
The whole madcap story of mixed-up love in this play illustrates the truth of the quote, spoken by Bottom after Titania falls in love with him under the influence of a magic potion. We see throughout the play that love causes people to behave irrationally. Titania, a queen, falls in love with Bottom, a comical, lower class man who, under the influence of magic, has been given the head of an ass. Helena follows Demetrius into the forest, even though he has told her he is in love with Hermia. Helena also invites him to abuse her as long as he will make her his, another form of madness. Throughout the play, love potions cause forms of zany madness that have everyone falling in love with the wrong person and behaving in ways that defy reason.
We've all witnessed what the heady feeling of first falling in love can do to a person and Shakespeare makes the most of it in this play. Right after he delivers his line about love and reason not keeping company, Bottom says:
The more the pity that some honest neighbors will not make them [love and reason] friends.
Then, in one the more complexly ironic lines in the play, Titania responds:
Thou art as wise as thou art beautiful.
She is blinded by love at this moment: Bottom with his ass's head is not conventionally beautiful, so saying he is as wise as he is handsome is, on the surface, saying he is a fool. It's a gag line. But what complicates the irony is that Bottom's words are wise: so perhaps, the irony is, that love--or the imagination behind love--actually might make him beautiful.
This play, with its focus on the madness of love, demonstrates both what can be most charming and most dangerous about love's unreason.