It used to really annoy me when older people would preach on about their experience, and how many lessons they only learned later on in life. As if being young made me stupid. Youth certainly doesn't make you stupid, just as age doesn't make you wiser, but I'd hope that there weren't many people who at least didn't become a little more wise as they gained more experience.
One of the life lessons that it took me a while to fully accept was that there isn't usually a single truth. That it is possible for two opposing things to be true at the same time. Learning this was actually freeing.
There is an ancient parable about a group of blind men, who are asked to describe an elephant. One describes the soft trunk, one describes the tail, another the legs, one the ears etc. They all get into an argument about their true description of the elephant, disclaiming against the lies told by the other men. Of course the story demonstrates that our own truths are limited by our own subjective viewpoint of the world. All of their descriptions were true, in part. Their truths could all exist alongside each other.
So, when we disagree with someone, it can be pretty powerful to remember that most people are arguing from their own truth, just as we are. The argument can get stuck because we are convinced that there is only a sole truth, that we must convince the other person of.
An example of this is dealing with people who are sometimes flakey or often late. My 'truth' about lateness is that if someone is important you are never late for them. Therefore is someone is late, you cannot be that important to them. However, this is not a universal truth, and it is therefore rather irrational to get into repeated fights over it. For others, they just haven't learnt to manage their time very well, or always underestimate how long something takes. They won't be able to understand your upset, as their truth is that lateness doesn't mean anything at all.
It can really help to ease confrontations to work on understanding why the opposing person carries their truth with them. What perspective are they seeing the situation from, which is different to yours? What experiences have they had which filter their understanding, which are different to yours? Once you work out that neither of you has to be proved wrong; that you can both be right, it's usually much easier to move forward.