Sock knitting is hugely popular for a variety of reasons.

Sock projects are much more portable than sweaters, they're ideal for gifting, and there are so many wonderful, beautiful, and fun yarns for knitted socks. And it's not as difficult as it might seem, really! Knitting socks is very straightforward, making them great projects for travel, or knitting at the game or while waiting for the kids to finish their sports practice. As long as you've got the right number of stitches and pay attention to the instructions, it will all work out.
One of the wonderful things about sock knitting is that it can be as simple or as challenging as you like. Once you've mastered a standard pattern, you make it over and over again. I find knitting plain socks with fun yarns very relaxing. Or if you're up for a challenge, there are all sorts of patterns and variations. Sock knitters all have their preferences: which needles to use, which yarn they prefer, the construction they find easiest, which heel and toe variations fit them best. Once you've tried your first sock pattern, you'll be well equipped to try others and form your own opinions!
Happy sock knitting!