I'll agree with Deltasix about packing a Bible for use both in combating boredom and improving morale (mine and others'). For what it's worth, Word Publishing Company markets a "world's smallest Bible" that measures 21mm x 80mm x 125mm (3/4 inch x 3 inches x just under 5 inches)--a size which makes it much easier to fit into a kit than your average paperback. It also fits the criteria of a lot of pages (1,205) and fine print (tiny). In addition, it's got 66 sub-books in it, so whether you're in the mood for motivation in hard times, appreciating the stars, erotic poetry, military tactical analysis, civilization-building social theory, moral instruction, or cautionary tales on using edged tools (2 Kings 6:5) you can flip to the appropriate chapter.
I have also taken to packing salt into my not-so-compact kits; I've got a box of coarse-grained "kosher" salt in each of the cars, to help in seasoning, preserving, etc.
As for other stuff, I've followed the advice of John "Lofty" Wiseman, author of the SAS survival manuals in their various versions, in putting a couple of tea bags in some of the less-compact kits for myself and the family. Reason, again, is morale: a little thing like that can really make the difference in people's morale. I remember a hike a few decades ago in the mountains of northern Arizona. It had been raining all day, was cold and wet. One of the guys I was hiking with had recently had leg surgery, and this hike was proving to be about at the limit of what he could handle--and maybe more. He fell behind the others, getting more and more discouraged. He sat down on a log, and was about to call it quits.
Before heading out, we'd mixed up a huge batch of homemade hot chocolate mix--using powdered milk, cocoa powder, and sugar. I had a bag of this uneven mix in my pack. I sat down with him on the log, and, while we talked, I used a stick to mix some of this in with some cold canteen-water. The resulting brew was lumpy, uneven, and pretty unappetizing-looking; but it tasted good. And, as I knew, the cocoa contained caffeine, theobromine, and phenylethylamine--stimulants which I figured, with the sugar, might boost the kid's spirits some. It worked. And, I think, more than the chemical effects of the chocolate, just having a treat of some kind got the guy's mind turned around. He got back up, toughed out the rest of the day, and then the next day. I think we did fifty miles by the end of that trip--even with that guy's recently-post-operative legs.
In a survival kit, I use tea instead of cocoa, etc., because tea is lighter, takes up almost no room, and also doesn't spoil. Also, the tea comes in foil pouches and seems to me a lot less likely to attract the attention of bears and the like. (I avoid strongly-smelling teas like Earl Grey for that reason. I've learned to keep my food-smelling items more or less in one place, so as to make it easier to separate them out from other gear and get them up into a tree in a bear-bag overnight; the more random items of food-smelling stuff you've got salted through your gear, the more likely it is that you'll overlook something.)