Why is it that the same 'inventions' are always used in these stories. It's always soap or shampoo/conditioner, cooking, or just plain ol' white rice
("b-b-but that's animal fodder!"). If the author is "really creative" they'll have the MC introduce coffee or Tea to the natives - who were previously too stupid to know how to serve it correctly
(despite it always being popular in the neighbouring country).
I'm shocked that none of those stories have involved the MC being the one to introduce the printing press, steam engine, motor-vehicles, or a more in depth look a guns
(it's always just a magic gun, rather than an actual gun).
Don't even get me started on MC's and friggen crop rotations! Is it so hard to do some selective breeding on plants and make a stronger and heartier variety of crop plant!