She really doesn't. I remember dropping her off for the first time to be boarded while I had to travel, and I knew the tail-wag was just because she didn't know any better.
When I had another two week travel assignment and needed to board her again, I waited until the last possible minute, drove ten miles under the speed limit, and talked to her the whole way: "Emma-Bean, it'll be okay. I'm coming back for you, I promise. I won't be gone long." (the last one felt like a terrible lie, but I said it anyway.)
I parked and opened the back hatch. Emma bounded forth with jowly smiles and that helicopter tail-wag that means she's really excited. There was no need for a leash. We walked to the door... well, I walked. She ran. And once inside, she disappeared immediately behind the counter without so much as a glance over her sweet, little shoulder.
I cried on the spot. Ridiculous, I know, but I don't have kids so you'll have to cut me some slack.
It's obvious that as hard as it is not to be missed, it's great knowing that she's got the kind of dog-personality that doesn't get too unsettled when I can't be around to kiss her on the head or scratch behind the ears.
And, I suppose I do enough "missing" for the both of us.