I am not a sweater knitter.
There are several reasons for this, and they all boil down to some combination of laziness, lack of attention span, practicality, frugality, and the commitmentphobia that has long since become a depressingly dominant part of my personality.
The main reason I don't knit sweaters is that they take forever. I don't have the longest of attention spans, and the only reason I'm able to read as many books as I do is because I read very, very, quickly. I do not knit anywhere near as quickly as I read, and once a project hits the one-month mark of continuous work, with each day that follows, the likelihood that I ever finish it diminishes. Exponentially. The fact that you have to knit things twice (sleeves, neck facings, hoods) makes it even less likely I'll finish one, given the fact that I already have a tremendous case of second sock/glove syndrome.
A second reason is that I have a hard time finding sweaters I'll get a lot of wear out of. Of all my handknit items, I wear my socks the most, closely followed by wintertime accessories like scarves, hats, and gloves/mittens/wristwarmers. That's because they go with multiple outfits, as opposed to being an outfit by themselves, and I prefer versatility in my wardrobe since I change it so much. Sweater designs fall out of style a lot faster than smaller accessories, as well. Beyond that, I live in the South. It doesn't generally get cold enough to warrant the wearing of heavy wool sweaters here. Even in the mountains, it's only Wool-Sweater Cold for maybe six weeks out of an unusually cold winter. As someone who has cold feet a lot, wool socks are a much better investment of my time, energy, and money.
This brings me to my third point: sweaters are really expensive to make. A general rule of thumb is that the price of a yard of yarn increases with the weight, or thickness of the yarn. Generally, lace yarn is the cheapest per yard, followed by fingering, then sport, then DK, then worsted, then the bulkier weights. There are, of course, exceptions to this rule depending on brand and fiber content, but it mostly holds true. While this has changed somewhat, the majority of English-language knitting patterns use DK or heavier yards, which automatically makes the cost of the project shoot up-- nevermind the fact that you need a lot more yarn for a sweater than you do for a pair of socks. My preference for using washable yarn for stuff I'm getting heavier wear out of (which drives the price of the yarn up even higher), it's even less likely I'll be willing to put up the cash for a sweater. So there's that.
The main issue, though, is that I am very commitmentphobic about fitted garments. This is due in large part to the devil of a time that I have buying clothes off the rack. Being short is hard, internet, and it seems like most clothing these days isn't sized for anyone under 5'4 (I'm 5'2), and that goes for knitting patterns as well. In order for a sweater to fit me, I'd have to heavily modify the design, and there's still no guarantee that it would actually fit. My options would be spending even more time on the project by unraveling and re-knitting it, or else cut my losses and toss it (given my previous comments on the cost of sweater yarn, this option is just as unappealing as the former). So while I often see patterns for lovely sweaters and think, oooh, I'd really like to have that, I can't quite bring myself to take the plunge, buy the yarn, and knit it.
So that's why I don't knit sweaters, in case anyone was wondering.