Probably the same reason it takes me 2 months to sew buttons on an otherwise completed sweater. I finish the body and see what the sweater will look like and then the excitement is over. I make the first mitten or the first quilt block or figure out that complicated lace pattern and then I lose my attention span. One sock syndrome a fellow knitter once called it.
In any case they are finally finished (buttons and all). All 100% wool and all top down raglan variations. I'm pretty sure they were all done on size 8 needles. The last one with toggles was wool purchased by my dad when he was in Ireland. You would think there would be wool everywhere in Ireland given it is a country known for its farms and sheep, but apparently my he had a horrible time finding yarn. France was also a difficult place to find yarn he tells me.
Whenever he travels I ask him to bring back local yarn or fabric. It doesn't quite make up for the fact that he's traveling while I'm living the life of an impoverished grad student (even though I graduated in May and it's now almost halfway through September), but it is better than a crappy t-shirt or little knick nacks I'll never use.