Fair question and I had too when I didn't have my own. The best way I can explain is - Think how stupid and emotionally strong is the average adult, now scale by a factor of what you think a person who has a fraction of experience and emotional strength.
It becomes scarier once you factor in that kids' learning is not linear, and a 12-13 old kid is simultaneously dealing with hormonal changes as well and you have a situation that most parents can barely deal with!