[Quiet Man Cometh]

Yeah. That's easy to do since chat and such is riddled with them, and they can be used a lot in creative writing for purposes of style, so it's easy to get used to them.

I think to avoid a fragment you have to indicate the specific thing you are talking about (THE dog, or THAT dog, instead of just "dog") and make sure it is a complete thought to go with it. "That dog" is not a complete thought as there is nothing going on with it. "That dog is black" is a complete thought, and a complete sentence. To just say "dog is black" for example, is a fragment because there's no context for the dog. Is it talking about one dog, or all dogs? My neighbour's dog? My stuffed animal that looks like a dog? Things like that.