Yes. I started messing around SO early last year and was busy for a few months solid.
Once I got to the 3K mark, the urge to come and build the rep disappeared for me (it was already shrinking after the 2K mark).
I'll come, read through some interesting questions, and might answer one or two sporadically.
In general, though, most questions are answered very quickly and there was very little value I could provide by adding a repeat of a solid answer. There were times when I would answer at about the same exact time as another person on a new question and it was almost vertabim (with the same Reflector code snippet and all! (My SO Answer, Doppelgänger SO Answer). That also contributed to the decline in addiction.
One other thing for me was the "Enthusiast" badge. When I saw it, it felt like a misnomer. It really meant "Addicted" and was a reminder to not let it become an addiction.