You learn some songs, strum and sing along, and it feels great. Every time you learn a new song, you learn the chords for that song, practise until it’s perfect, and then move onto another song.
Over time, you build up a large library of chords in your head, and if someone names a chord, you can probably play it.
Sounds pretty good, right?
But here’s the problem:
That knowledge is random, disconnected, scatterbrained…
You have no clear picture of how every chord fits together, what sounds good with what, and so on, because you learnt them randomly, and you learnt them by name, not by how they fit into a bigger musical picture.
You can’t see, hear, or understand how chords in different keys are related, and whenever someone needs to change the key, you rely on the same chord shapes and barre chords so you can just move up or down… but you don’t really know how to do it in your head.
It’s fractured knowledge.