Good Debt vs Bad Debt

What is the difference between "Good Debt" and "Bad Debt"? Is there a Difference? How can we tell? I shall attempt to answer these questions.
Lets start with the bad debt. We all know what this is. Credit Cards are the first thing to come to mind, followed by personal loans, car loans, title loans, etc. We should avoid these debts, and do our best to pay off what we have quickly.
Good Debt: I have been taught about this good debt, and about how it can help further you financially. I was taught about it's ability to make you wealthy. I've been taught how to manage it, and make it go farther. I have been taught how to leverage it and make it multiply. I am talking about a mortgages, home equity line of credit, or second mortgages, etc.
These are wonderful! you can buy a house - on credit - make it nicer - on credit- borrow money against it (credit) and get another home - on credit -! the process is easy! and with in a few short years you can have multiple properties! Money will fall from the heavens, someone else will pay your bills, nice cars will always be in your driveway- life will be good!-Right?
WRONG!!! Good debt is a myth! There is NO SUCH THING AS GOOD DEBT!
I have debt, Don't think I am perfect. In fact I have close to 1/2 a million dollars of this "Good Debt" and I could easily double it this year if I desired. But I don't desire.
I have been taught wrong in the past. I believed good debt was ok to have. I believed it would make my life better.
I know many people (once my friends, mentors, and associates) who have gobs of this good debt in the form or real estate, as I do. Now they have gobs of problems.
I know just a handful of people (now my friends, mentors, and associates) who also have much real estate. But they have it with out the "good debt". They have it because they OWN it. no payments, no debt, nothing. Just own it.
So, What is the difference between good debt and bad debt? Nothing. It's a trick question. We should not obtain any type of debt.
But Brian, how do I buy a house? How do I go to school? I am not a die hard no debt at all person. We all need a place to live. Weather you rent or buy, we should only pay 25-30% of our income to our home. If you can purchase a home and not spend more than 30%of your monthly income, then go for it. If not, save until your down payment makes the mortgage small enough that you can. If you need to go to school, do it as cheap as possible, and pay it back quickly.
But Brian, how do I buy a nice car? You need a car, but get one you can pay cash for. Save some money, look for a good deal, and buy it.
If we avoid all types of debt, then we truly become free. We will owe no one. We will be controlled by no one. We can live life to the fullest!