Yeah, I think that's a good idea.

I take leftover roast chicken or pork and mix with bbq sauce to put on sandwiches or jacket potatoes the next day. Fried rice is another good alternative for leftover meats and rice. Also, leftover taco / burrito meat can be used on jacket potatoes with salsa and cheese, or a taco salad, quesadillas, enchiladas, chili, or some other variation. I make chicken stock with leftover chicken carcasses and freeze it to use for soups and sauces. Usually just making some stock uses up some leftover raw veg and herbs in the fridge that might be looking less than appealing (carrots, celery, parsnips, leeks, etc. are all good for making vegetable or chicken stock or what have you.) Leftover mash is great for potato cakes or fish cakes.
I think the worst is when you cook something you don't really like, and so you don't eat much of it, and then there are loads of leftovers and if you didn't like it the first time, you definitely aren't going to like it the next day. Sometimes there isn't really a way to change it up and it just goes to waste. But, we have the pets who can help out, depending on what it is, and my in laws live across the street so sometimes I take leftovers to them if I think they will like it.