I mean, I don't miss him like I miss the_overqual or wshaffer or somebody who's a personal friend. But I think he moved to Amber to be their Platonic essence of mailbeing. That's what I think. And I wish they'd send him back, because how important is it that the denizens of Amber get their mail delivered properly? For me, not very. Doesn't help me much, is what I'm saying. Given that they're fictional and all.
If you're thinking this is like the time I missed my former bookstore clerk, you're probably right. (Except that I miss Will more than Lou, even though I buy SF far less than six times a week.) But you all remember how well that eventually went. Well, at least some of you do: I went to Minicon, and I met madmanatw, who sees Will all the time, and so he could verify that Will was okay, or at least as okay as one might expect, and I was so happy I kept telling random friends and acquaintances. So maybe Lou is okay, too.
There's a reason timprov makes frequent reference to the "Dharma and Greg" episode where Dharma is considering adopting her grocery clerk's baby. But Lou was my mailman for over four years, so naturally we had a friendly relationship. It's not like he was a substitute one weekend or something. I only know a few of our substitutes.