I like gravy.
It's important, because some meats, especially beef, need to be rested after cooking. A good sirloin joint, for instance, needs to be rested for some twenty minutes to allow the muscles to fully relax, so the meat is as tender as it can be when it gets to the plate. It is important to allow the meat to cool.
That's where gravy comes in. Gravy adds moistness to the dish, and also enhances the flavour of the meat, if properly made. In addition, it provides heat to replace the heat lost when the meat rests.
I usually make my gravy with the meat juices. This way, the otherwise-lost bits from the cooking are not wasted. I add a little mustard powder. Or, sometimes, Dijon. Some bouillon, the swiss stuff. Thickens and seasons, like Bisto, but without adding alien flavours.
But my tip for a good gravy is this: ALWAYS add a little wine. And make sure it's the same wine as you're going to drink with the meal.
Fusion. Fusion gravy.