You seem to be operating under the assumption that "love" is something that doesn't help people get happy. If you're trying to optimize for personal happiness and love (in whatever form) enhances your ability to be happy and/or directly causes you happiness, love is a perfectly rational thing to do.
You say:
So then, the idea of love bothers me, because you sort of throw rational thinking out the window, stop asking why something actually matters, and just decide that this significant other intrinsically matters to you.
But that doesn't have to happen. You can keep thinking rationally about love, even when under its effects. It's not because we are wired to love by evolution that the love for my family, partner, friends... stops being valuable and gives me happiness.
And I don't know why I'm typing all this, because you seem to have a very narrow definition of love, namely the very specific timeframe in the early part of a romantic relationship. Love is a lot broader than that.
The obsessive part you describe is love, but so is:
Something along the lines of enjoying each others company, and caring for one another and stuff, but not being blindly committed to one another, and being honest about the fact that you wouldn't do anything for one another, and will in fact probably grow apart at some point.
And if I had to answer your opening question:
Yes, love tends to be a good idea, but you have to be specific about what type of love and to which degree.
ETA: After re-reading Feeling Rational, I think that the statement "Love is not something that can be destroyed by truth." works better than everything I wrote above and more or less sums up what I'm trying to get across.
I've searched around on LW for this question, and haven't seen it brought up. Which surprises me, because I think it's an important question.
I'm honestly not sure what I think. One one hand, love clearly leads to an element of happiness when done properly. This seems to be inescapable, probably because it's encoded in our DNA or something. But on the other hand, there's two things that really make me question whether or not love is a good idea.
1) I have a very reductionist viewpoint, on everything. So I always ask myself, "What am I really trying to optimize here, and what is the best way to optimize it?". When I think about it, I come to the conclusion that I'm always trying to optimize my happiness. The answer to the question of, "why does this matter?" is always, "because it makes me happy". So then, the idea of love bothers me, because you sort of throw rational thinking out the window, stop asking why something actually matters, and just decide that this significant other intrinsically matters to you. I question whether this type of thinking is optimal, and personally, whether or not I'm even capable of it.
2) It seems so obsessive, and I question whether or not it makes sense to obsess so much over one thing. This article actually explores the brain chemicals involved in love, and suggests that the chemicals are similar to those that appear in OCD.
Finally, there's the issue of permanence. Not all love is intended to be permanent, but a lot of the time it is. How can you commit to something so permanently? This makes me think of the mind projection fallacy. Perhaps people commit it with love. They think that the object of their desire is intrinsically desirable, when in fact it is the properties of this object that make it desirable. These properties are far from permanent (I'd go as far as to say that they're volatile, at least if you take the long view). So how does it make sense to commit to something so permanently?
So my take is that there is probably a form of love that is rational to take. Something along the lines of enjoying each others company, and caring for one another and stuff, but not being blindly committed to one another, and being honest about the fact that you wouldn't do anything for one another, and will in fact probably grow apart at some point.
What do you guys think?