Gas fireplaces can be great if you properly maintain and service them. But if you get lax about it, all kinds of problems can ensue. Sometimes the pilot light goes out, you can get soot forming, it might start making strange sounds. Or, worse yet, you could get that distinctive rotten eggs smell, which means that the natural gas could be making its way through your living room. And natural gas is highly flammable, so it won't be safe to smoke, or light a match,...