I think one thing that makes balanced decisions hard is the feeling that we're publicly voting against the option we didn't pick. We may know that the two sides were balanced, but, in normal conversation, people don't talk very much about levels of confidence, so the choice may signal that we had a strong preference. When we're choosing between two good things (or two people), it looks like we didn't care that much about the one we didn't pick. And it probably won't help to say, "No, no, I care, I'm just indifferent between these choices!"

If we don't want to use dithering as a signal that we are attracted to both options, what are some other options when out in conventional society? (I've just trained my friends to take me literally if I preface a statement with "Take me literally" which really speeds up choosing a restaurant discussions).

Well... if you can't decide between them, they must be around equally appealing, right? Equally balanced pros and cons? So the choice must matter very little - you may as well flip a coin. The alternative is that the pros and cons aren't equally balanced, in which case the decision should be simple. ... I do think there's something to be said for agonizing over important decisions, but only so long as the agonization process is currently going somewhere, not stuck.

I have a hard time applying this to those choices that I most associate with agony, either my own (break up with someone or not) or imagined (jump out of a burning building or stay; give up one child or the other).

I was reminded of this piece when I was playing Catan. It so tempting to agonize over where I should put my first settlement, but it's not worth wasting the other players time.

If a choice is hard, that means the alternatives are around equally balanced, right?

Subjectively, sure. But isn't the important factor the expected marginal utility of further analysis?