When I try and explain to people that my hobby is typesetting or typography, it’s rather hard to justify. Especially to engineers who might not appreciate the æsthetic reasons in the first place. (I kid.)
Now, I’m not going to attempt such a justification now besides saying that my primary reason is that it helps people. But being interested in typography in the first place comes from some part of my, ahem, soul that tries to cling to the idea that perfection should be achieved where possible simply for the sake of doing so — and the subsequent benefits will be evident.
Well, here’s some small consolation for me. A while back Amar at UIScape referenced a research article looking at the effects of “fine typography” (not macro-level typesetting like linewidth and fonts but rather the micro-details like kerning and ligatures) and found that while the reading speed and comprehension and even preference between the two samples were equal, significant effects could be found in other areas:
[P]articipants turned out to frown less, and could therefore be said to have been “happier”, when reading text with the enhanced typography. […] [P]articipants who read text with good typography did perform better on [creative problem solving tasks after they had done the reading].
I find this amazing and it pleases me no end. I hope that more studies like it will corroborate their findings, but for now I can confidently state: “the documents I create will make you happy”.