Comfy restaurants-what makes them work?

It's all about creating a setting that’s warm and inviting. That's a main ingredient in what I look for when deciding where to eat out.

Let's talk chain restaurants.
Panera Bread Company's mission is to "bring bakeries back to neighborhoods across America" ala, European neighborhood bakery-style.
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They work to differentiate themselves with an emphasis on interior design several steps up from traditional quick service. Seating is provided in "zones". There's a "cozy corner" with leather sofas and easy chairs, a "community area" with high top tables that can be pulled together, and a traditional dining room. Lots of autumnal colors- rusts, brown, pumpkin, sage, with pops of purple and maybe some navy here and there.
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Panera is also trying to attract "chill out" business--people who come in between breakfast and lunch or lunch and dinner to have a pastry and coffee, sit on a comfy chair, and, relax in a way not possible in most fast-food restaurants. (source)
Ruby Tuesdays is another chain, set to embrace the idea of a welcoming interior. They recently went through a major overhaul, revamping everything from their logo, to their interiors.
Here's their old look:
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And their new one:
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As Brand New so elloquently put it, "Gone are black- and white- checkered tablecloths and the hodge-podge of sports memorabilia that adorned the walls and were reminiscent of Applebee’s or TGI Friday’s".
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Hm, I'm seeing a bit of a trend here, with the autumn colors- lots of warm, muted tones, with splashes of brighter colors, light red or gold, here and there. And lots of different seating arrangements. Perhaps an interior designer, with knowledge about restaurant design, could comment on that?

I went into a local Thai restaurant some time ago, and could barely stand to wait inside for my take-out order, let alone dine in. The entire place had been painted in a dreary gray blue. And I do mean everything- all the decorations on the walls had been spray-painted to match the walls. I'm not talking a sophisticated light gray, but a medium heavy tone that reminded me of wet clay. I wish I could recall the name of the restaurant, so I could drive out there and snap a picture for you to see. Anyways, it just struck me how important color is to developing the mood, ambiance, and even perception of value, in a restaurant.