This comment was left on the YouTube video of 20 Tips for Guys in their Twenties:
“Thanks for the tips sir! I am still 17 years old and without a father to give me advice like this, your help is extremely helpful.”
For extra benefit, this list is specifically targeted at teenagers:
Gossiping. Leave it to girls.
Worrying. Whatever it is might not happen, and worrying about it won’t stop it anyway.
Faultfinding. You’ve got plenty of your own.
Dwelling on imagined slights. Only a big ego bumps into everything.
Letting little things affect you in a big way. Eagles don’t peck with pigeons.
Thinking life is not worth living. Your ancestors and parents worked hard for you to be here. Honour them.
Talking about yourself more than you ask people about themselves. You’ll learn more this way.
Speaking badly about acquaintances or friends. If you’re a true friend, say it to his face.
Clinging to past pain. All pain passes.
Pitying yourself.
Writing anything when angry.
Bemoaning a lack of opportunities.
Seeing the worst rather than the best in others.
Thinking you’d be happier elsewhere. You’d still be there.
Belittling people you envy.
Telling your problems to anyone who’ll listen. Blood in the water attracts sharks.
Imagining what you’d do in someone else's place rather than doing your best in your own.
Dreaming about the future rather than making the most of the present.
The above points apply not only to teenagers but to mental adolescents of all ages.
If you can think of someone who’d benefit from this, please share it.
Some of those I did way before 18, and some took me years after being 18 to figure out.