My mother was a teacher. My wife was a teacher and a principal. My daughter is a teacher.
Me, I'm a DBA, but living inside technology and working for one company, it can be hard to really learn about that technology. It's much easier to just do what you know and keep doing it, and you never get a chance to explore those areas you don't work with.
So, I decided to become a teacher, and earned my MCT certification.
All of a sudden, I had to become familiar with aspects of SQL Server I'd never touched before (like replication). People ask questions that are really important in their environment, and look to you as the teacher to provide guidance. Saying "I don't know" isn't an option. Saying "let's find out" does so much for both you and the student. You get to discover all the different ways that others have found to solve their problems, and you both learn from it.
Now I'm a consultant, and last month a client was complaining about how much a waste of time and money consultants are. I looked at her and said "wait a minute, I'm a consultant!"
She responded "No you're not, you're a teacher."