“Love is blind,” goes the idiom coined by Shakespeare, and we human beings do seem to be wired that way. One study done by University College London researchers in 2004 suggests that feelings of both romantic love and maternal love hamper critical thinking in the brain.
It would seem, however, that G-d wired human beings that way to give us an advantage AFTER we’ve committed to a relationship. After we have thought about what we’re getting into, after we have used our G-d-given critical thinking processes to decide whether the person in question is the right spouse for us – that’s when the feelings of love are supposed to help us gloss over the imperfections in our spouse.
But during the decision process, Tu B’Av tells us, have your eyes open and critical thinking on, for two reasons:
1) So you don’t make a mistake in who you pick
2) So you don’t have a claim that you made a mistake in who you picked
Huh? Where does Tu B’Av tell us that? Isn’t it all about the maidens of Jerusalem going and dancing in the vineyards in borrowed white dresses?
Well, yes. But let’s listen to what those maidens are singing as they dance…
“Young man, lift up your eyes and see what you are choosing for yourself!
“Don’t look at beauty; look at family! For it says, ‘Grace is falsehood and beauty is vanity; a woman who fears Hashem – she shall be praised.’”
The Gemara tells us that this statement of the Mishnah is the refrain that was sung by only some of the maidens who were dancing. But there were others, depending on who the woman was and what her virtues were:
“The beautiful ones would say, ‘Look at beauty, for a wife is for beauty!’
The pedigreed ones would say, ‘Look at family, for a wife is for children!’
The ugly ones would say, ‘Take your taking for the sake of Heaven, as long as you crown us with gold.’”
To go into detail about each category and the message behind what they were saying is beyond the scope of this post. But within the context of our discussion: the maidens were telling the young men (whether they were actually singing in front of them, or whether their songs were addressing an anonymous male archetype):
“Lift up your eyes!” Don’t go through this process with your eyes closed. Don’t let love – or laziness, or anything else – blind you.
“See what you are choosing for yourself!” You’re making a choice. Some of us have the virtue of beauty. Some of us have the virtue of a family of high social stature. Some of us have traits that will bring you spiritual gain. They’re all virtues. They all have value. But you’re not going to find someone with all of them.
Realize that, young man. Realize that your wife will have virtues – and that there will be virtues out there that she is lacking. Make a critical thinking decision now about what is really important to YOU. Realize that you are making a choice.
That way, when a few weeks, or months, or years into marriage, you are reminded about a virtue that your wife doesn’t have… you can remind yourself that you made a choice. That you lifted up your eyes, you knew you couldn’t have everything, and you chose for yourself.
And THEN you can work on letting love blind you.
Note: this is as applicable to females as it is to males.
 Taanis 4:7
 Taanis 31a
 Etz Yosef on Taanis 26b