Why won't my sim sit still?

I've noticed, since I do alot of building, that separating rooms, even with arches, (or at least in build mode if it's cut technically into different rooms) cuts down on them randomly wanting to do other things. Like if you have the fridge & stove in the same small room as the TV, they will more often than not go watch TV instead of finishing cooking, unless the TV is out of watching range where they're cooking in a large room area.
For computers, you can set security settings. Only allow certain sims to use, of just lock it out for everyone until you change it.

As for books, there is a small small mod fix for that. Also for putting things in inventory instead of dropping them everywhere or back on the bookshelf. Very handy mod! But otherwise, maybe you should just lock them in a room until they finish the book, heh!

EDIT: I guess I'd be a mean teacher, "You're in detention in that little room until you finish reading that plum book! And I'll be asking questions about it, so I suggest you actually read it!" :D