Great stuff:

If you buy my product but don’t read the instructions, that’s not your fault, it’s mine.
If you read a blog post and misinterpret what I said, that’s my choice, not your error.
If you attend my presentation and you’re bored, that’s my failure.
If you are a student in my class and you don’t learn what I’m teaching, I’ve let you down.

via Seth Godin (read the full article)