Ego is the evilest thing ever

Why does people only learn after they've suffered? I've told you countless times not to do it, but still you did. When you continue to do, I know this day would come. The day where you say, 'I shouldn't have did it. Damn'. Told you. Ego is the evilest thing ever. I told you not to retaliate. Told you not to fight back. But what's the result? You did. And the consequences? Got expelled from school. Sometimes you really need to listen to the voices of your friends. True friends never harms you and make you do the wrong things (together, at least). A minor wrong step in the past can cause a storm of disappointment in the future. Ego..., it harms you in every way possible.

Sometimes I really think I've known too much stuff on the pursuit of life at a tender age of 18. People at my age are super ignorant at stuff, am hard to differentiate the good from the bad, and vice versa. At only a young age of 14, I know smoking is bad for health, drugs harm and numbs the brain; casuing damages that can last a lifetime. I learnt that money is the only survival tool in this world. There is no full-trustworthiness for human beings, even in your closest kin. I learnt that power and money is the ultimate weapon in this era. I learnt that loneliness is the most non-physical desolate a human can ever suffer. I learnt that ego is the evilest thing in life, being able to bring you from the top to the bottom in unimaginative seconds. I learnt that the most painful emotionally feeling is to see your loved ones suffer right before your eyes, and not being able to do anything to help, et cetera, and the list continues.

Why does human beings learn only when they are at the doorstep of regret?