That you can give your children the benefit of your experience and they will avoid all the difficult lessons and get right down to business.   No. Every child must do things on their own way.  They run helter skelter straight into the abyss against all your warnings.  Such is life.
 1) If I knew it would hurt so bad to be old, I would have taken better care of myself and 2) most shit never changes.

• Time goes by faster as you get older.
• Your best route to success is learning how to deal with failures.
• Do what you enjoy.
•  As I grew from an adolescent to a young male, my life priorities have considerably changed.
  
  The following have become more important:
  
• Career. Work is what I do most of the time I'm awake. I'd better love what I do and be inspired by it.
• Stable relationship based on trust. Love is different that it used to be, it's turned from acute to chronic. It used to be blazing emotions and now it's more like "home sweet home". It's not better nor worse, it's just different.
• Money. It keeps me safe.

The following have become less important:

• Friends. They used to be everything to me, but life has changed. My direct circle of relationship now takes all my attention.
• Social acceptance. This used to be important when I made new friends, but I can't accommodate any new friends now.
• Those little every day fun things. I don't need them anymore, it's the end that matters.
•  How precious life is and everything can end in a second.
•  When dealing with a difficult relationship, focus less on figuring the other person out and pay attention more to how you feel when you’re dealing with that person. Usually, you can’t understand why you feel the way you do with them until you’re away from them.
  Whenever you’re doing anything compulsively(shopping, alcohol, workaholism, drama-filled relationships), you’re avoiding a feeling. The only way to stop the compulsion is to experience that feeling in a safe place. 
  People are more likely to read bullet points than paragraphs.And people are more likely to read numbered lists than bullet points. 
  You are not responsible for making someone else feel a certain way, do a certain thing, sparing them pain, or making them feel better, no matter how much you think you are helping them. In fact, trying to do so is often about making you feel better. 
  Authenticity, aka compassionate honesty, about yourself and towards others is the only way you will ever find freedom in life.
   You are unlikely to really understand what was going on in your family when you were growing up until your mid-thirties. So hang in there; it really does get better. 
  You’re probably not crazy. You probably grew up in a dysfunctional family. There’s a BIG difference. 
  Wear sunscreen every day, especially if you're fair-skinned. Age spots and wrinkles suck. 
  Hitting bottom is a blessing. It’s a letting go of what wasn’t working and having freedom to do it better.  
  Learn to think critically. Question. Be skeptical. This is how you become who you are, not a carbon copy of those around you.