I'm specifically looking for the difficulties people have been having learning linux in order make it an easier process.

I'm doing some research on people's experiences learning linux, and I would really like to hear from new users and people that are already familiar with Linux.

Here's my questions:

1. How difficult do you find learning linux?
2. Why are you learning linux? Are you trying to get a career doing linux?
3. Did you take any classes? If, so what did you like about them? What could be improved?
4. Did you purchase any books or other material to help you?
5. How have you practiced what you've learned?
6. Have you taken any tests or certifications to gauge your progress or certify your knowledge?