When I had just one (a well behaved showdog) he'd react like a cat. He'd barely lift his head when I left and when I returned I'd find him curled up tightly in the same place I'd left him hours before - under the foyer table in clear view of the front door, greeting me with a languidly raised head and a bored look that read "Oh, you're back?" He never barked at anything.
Suspecting he wasn't happy I got him a second dog as a companion and she promptly taught him to bark and jump excitedly on me to greet me when I got home. Because it'd be rude for them to jump on guests and I'm invariably lugging something through the front door I retrained them both so they'd wait expectedly until I sat in a designated spot to greet me, at which time I show them a lot of love. When I leave they don't try to stop me but they've each perfected deploying the most soulful, angst-ridden "What did I do wrong?" stare at me. I'm told that when I leave the house even for a few hours they'll mope and stare out the window until I return, a dependence I'm not proud of fostering. But they never howl, bark or get destructive, and when I take them with me on errands they get the most supremely happy, relaxed and satisfied looks on their faces, as the male shows while using the female as a pillow - check out how he splays himself out now: