Various reasons and influences could explain why a parent may have issues with raising well behaved teenagers.
Perhaps the issues start during the teenage years. Hormonal changes, and identity issues could explain why teens may act out. Parents may make things worse by setting too many/too large expectations or too little expectations. It also could be poor communication, times change and parents may simply not understand their teenagers due to this. They may talk too much and do not listen as much as they should
In childhood and teenaged years common parenting mistakes are: not taking your kids feelings seriously (boys don’t cry, it’s not a big deal, etc.)
Overindulging your kids (typically spoiling)
Failing to lead by example (expecting respect when you don’t show respect, etc)
These factors may cause teens to act out.