Sliced bread. Sliced bread defined all great things! I mean nothing great came before sliced bread, right?
Indoor plumbing. Huddling with friends/family to keep warm in a three-hole outhouse in January when it -5 outside is not exactly appealing.
Life must have really sucked before... Women Hot running water Carburetors Penicillin Guns Sharp sticks Soap Explosives, and/or fireworks Beer Pain relievers Rockabilly