What differentiates the Expert versus the Enthusiast? Have you worked with enthusiasts before? What's the key to becoming the expert?

A soft question but it's been on my mind for a while.

I've worked with people before who have an enthusiast knowledge and attitude, they will learn "just enough" to get the job done and it seems to work most of the time. Sometimes they will ask me questions that make me concerned at their level of knowledge (i.e. a question you would expect a novice to ask, not a senior). I had a chat with a friend about this and he came up with the "Expert versus Enthusiast" idea as he's an Engineer and sees this a fair bit with friends who are Automotive Engineers vs. Automotive Enthusiasts.

Some questions:

• Has anyone worked with an "Enthusiast" before?

• How would you say that an Enthusiast differs from an Expert in our industry?

• What's the key to becoming an "Expert" in the field? Is it a narrow focus on mastering the fundamentals? (TCP/IP for instance)

• Is the "Just enough" attitude okay if used in moderation? (Learn just enough about say 'Technology X' to get the job done)

My personal question: I sometimes take the expert mentality into all of my pursuits. Which I'm starting to believe is negatively impacting me. I'm starting to think that's it's important to have that expert base of knowledge but to put on the "just enough" hat when dealing with day to day issues and problems. Sometimes you can invest an inordinate amount of time in learning something academically from the ground up, only to realize if you learnt the important parts only (the just enoughs) to get the job done you might never see it again and deeper commitment would have been wasted.

Is IT really a game of knowing the trunk of the knowledge intimately and learning the leaves of knowledge "just enough" to get the job done?

Does anyone have thoughts on this, I'd be curious to hear.