Personally, I find my day job technically challenging, fun, and often rewarding, but I don't really find it fulfilling in some deep meaningful sense. I feel useful but not meaningful.
It took me a while to realize that this was the problem I was having -- and that just switching from software engineering job to software engineering job wasn't going to change it -- and I am still at a crossroads as to what to do about it. I'm not sure if I should seek fulfillment from outside my career -- family, community, a craft, a cause -- or if I should change my career to one I (think I might) find more fulfilling.