I enjoy watching videos of old "forgotten" food items from the 1930s through the 1970s. Not all of those dishes are gone and forgotten. I freaking love tuna melts on rye, but keep them simple, with nothing more than canned tuna, flaked up, finely diced celery, mayo, and some salt and pepper in the tuna salad.
Casseroles are also good, but they really don't take much less time to prepare, dump in the dish, and bake (if any) than it would to bake some chicken breasts, steam some broccoli, and make mashed potatoes to go with it. Hello. For shepherd's pie, the meat needs to be cooked ahead of time, as does the mashed potato topping. For tetrazzini, the bechamel needs to be made ahead of time, along with the sweated down mushrooms and celery. The spaghetti can cook while all that's going on, but it still takes a good half hour before it's ready to toss in a glass casserole, top with some sort of bread crumbs, and let bake for another 30-40 minutes.
You can cheat with condensed canned soup for some things, but the end product is not as good.
Still, all of it beats the living daylights out of the jar of baked beans and a couple of hot dogs my mom left the babysitter to feed us when my parents went out to a dinner party. I really hate hot dogs. Diced up, they're okay for training a dog. A good bratwurst, otoh, grilled, is goff with some whole grain mustard.