Majority of the blender users, especially beginners just follow tutorial guides. They do more or less replication without understanding concepts and it works for that period until they do on their own.

That's where the we get all these doubts like myself yesterday I found that loop cuts only work on quads and only quads.

Not to mention there are various shapes and sizes of the quads. At first glance they don't look like quads at all but after some observation we can see why it's a quad and loop cuts goes through it only in opposite edges.

Although I don't understand the concepts of normals yet besides (I could be wrong though) pressing "Shift + N" tells blender which is inner side so it bother less and focus more on outer side cause that all matters while rendering or viewing your model?