You start to learn something. You don't know what to google. You don't know the luminaries. You don't know what are stupid questions. You don't know which are the good books, and they are all £90. You might not know a good book when you saw it, except that it seems to make sense to you, where others are demeaning slammed doors. You don't know enough to just get started and incrementally improve at any rate at all.
Education is artificial enclosures and screens on this terrifying commons: ignore those cliffs, forget that vertiginous sky, stay in here, you will be safe to get strong, here is a nice story. StackExchange is a chain of lifeboats on the open sea of research, vanishing to the horizon.
Most educated people never leave the enclosures, and mistake the limits of the curriculum for the limits of the world. (In this way, it's possible that the American general education philosophy - so admirable, so civic - could narrow minds.) In economics this "101ism" is particularly pernicious, since even honest specialists, those operating well beyond the screen, can't communicate their technical results to the media, so almost all discourse takes place inside the fake, narrow enclosure, with endless fruitless illiberal results.
In fields where it's impossible to know if you have gone astray - everything except the formal sciences - the work feels nicer but is sadder, considered on a proper timescale, of centuries. There it is almost inevitable that lives will be ploughed into the soil and merge with the stream of decomposing misguided theses. In the formal sciences this is only very likely.