Well, they definitely haunt me when I haven't gotten them down yet, but when I do cement it into words ... they're still there but they're drifting off as I'm content now to let them go, secure in the knowledge that what I just witnessed in my head is in a concrete form and won't be lost after I take a nap And they're gone after I take that nap, but I don't feel that absense ^^;
I don't lose interest in my story once it's completed though. I just completed one and I only wish I can forget about it for a while and stop wanting to shove it in the face of everyone I meet and ask for their reactions :'D