Magic-Users are insufferable Nerds
Recently when thinking of the design of my fantasy heartbreaker mess I have decided that knowing given type of magic has a cost - you don't have real life background skill. And I have found out that having skill [Pirate] makes you versatile and having skill [High Magic] makes you very narrow focused. If you don't research spells at the moment, prepare them or fo stuff with them you are like a child in the fog.
And then it hit me. We think of wizards as these wise scholarly dudes like Gandalf or Merlin. But the are experienced, traveled, old. Who is the young adept of wizardry who just left the tower in order to wander the realm? They know nothing, they just spent ten to thirty years of their life learning about spells and reading books. But not mundane books. These were books focused on the arcane. You just spent your life learning reality altering secrets of the universe and you're going to tell me you read something about local geography too? Why?
So I came to the conclusion that inexperienced Magic-Users are basically Pratchettian magic nerds! They are snobbish, dirty pricks, probably pimply and barely knowing how to care about themselves. They just finished their training and have no experience, just very obscure knowledge on the verge of mathematics and philosophy. It makes sense that starting magic-user character would have only [Magic Type] skill. Because they haven't lived through anything else in their life. NERDS!
Disclaimer: author of this post considers himself a nerd. He cannot change it despite of decades worth of effort. Nerd.