just a trial of strength which can be met by a stronger authority
Yes this. I would be mortified if my daughter spoke to me like dirty.
Teenagers can be very out there and live things more intensely but that's still not an excuse for disrespect. I have been nothing but understanding, kind and parent in a way that my daughter can come to me with any worries or thoughts she has and we can discuss them without judgement of any kind. I taught her nothing but respect for others that respect her (and this is very important) some adults are very condescending towards teenagers and that's a no no.
I have the authority, but my authority isn't applied forcibly or unfairly.
Open communication since they are little plays a big big part in how they treat you in later years, parents need to be there for their child, discuss what happened at school, discuss friends, discuss emotions, help with homework, understand what the homework entails, discuss teachers, discuss actions that they see and how that makes them feel, discuss which behaviour is most likely to upset someone and how that makes them feel, be also an example for these things. The way you act towards others is being watched by your kids, they will mimic you as they will mimic friends and other influences outside the house, it's up to you to discuss it and show different if you see the train derailing.
Be genuinely interested in your child, give them love and affection, make them feel secure and special and you will see such a big change.
Some family dynamics don't allow for all of this to take place but it's a must that as parents we need to be more present in our children's lifes, teenager years are also when some parents start full time work they have little time now for being present, parents leave them to their own devices or to their own "little world" because they are now "older", and they don't need as much attention and faffing around.
Wrong, that's when they need it the most.