My wife did a series of posts (here, here, and here) on two variant readings of the Mishna/gemara which lists the groups of girls who would go husband seeking on Tu b'Av and what they would say. The text of the Bavli at the end of Ta'anis lists three groups of girls: those who were beautiful, those with yichus, and those who were ugly but asked their chassanim to marry for the sake of Heaven. The Ein Ya'akov divides the last group into rich girls who said to marry for money, and poor girls who had nothing.
R' Tzadok cites a Pri Eitz Chaim that sees this marriage dance as a hint to the relationship between the Jewish people, the kallah, and G-d, our prospective bridegroom and the 4 groups of girls as corresponding to the 4 letters of the Shem Havaya. While it is beyond our ability to fully understand these matters, there is one R' Tzadok-ish point worth taking note of. Had you asked me I would have said that the ugly, poor girls correspond to the last letter hey in the Shem Havaya. That last letter hey is a hint to this world, the lowest sefira of malchus, the furthest point from G-d's direct grace. Not so, says R' Tzadok. The ugly and poor girls are actually a hint to the letter yud, the most spiritual letter, hinting to the highest point of keser, the greatest experience of G-dliness.
The problem with religion is we get all caught up in the trappings, whether is a geshmak chiddush of R' Chaim or a tasty kugel and cholent, or even the beauty of certain mitzvos. When you strip away all of that, for many of us there is not much left. But the truth is that when you strip away all of that stuff, that's not the end of religion, but the beginning -- at that point all that is left is you and G-d, one on one. Pretty scary thought. But that's why when you are done talking about yichus, money, even who is a bigger talmid Chacham, when you don't even want to talk about that stuff or can't talk about that stuff because it just doesn't apply, then you are left with the first yud, the keser, the start of it all, the real ikar and real l'shem Shamayim of it all.
Maybe that's why Tu B'Av comes right after we complete our week of shiva which began on 9 Av (see R' Tzadok). When there is no more Beis haMikdash, when everything we had is taken away, only then can we begin to rediscover what is real and meaningful. And with that discovery will will hopefully be led to the dedication of a new mikdash, which as the Pesikta writes, will occur on Tu B'Av, b'meheira b'yameinu.