Things that affect you aren't important?
Not everything is important. In fact, the word "important" expresses a relative level of significance. If everything were equally important then the word "important" would be meaningless.
Examples of levels of importance:
Breathing - extremely important. If I don't breathe, I will die.
Writing this post - not at all important. Nobody cares whether I write it or not. Not even I care that much.
Getting to work every day - quite important. I need to earn money to live, however, I could get another job if necessary.
How I get to work - not as important. It really doesn't make that much difference to my job whether I drive or walk to get there. Or, given that I now walk, whether I take route A which is noisy or route B which is quieter but takes about 30 seconds longer.
Just because something affects you, it doesn't automatically make it important. Everything affects you to a greater or lesser degree, but not all of those effects are equally important. Some of them are not important at all.
Would how I behaved in any previous discussion affect how you approached this one?
Probably, but you would likely say that having the discussion is more important than reaching an agreement. In fact, you're such a strong believer in this principle that you will carry on arguing about things that we already agree on. Whereas I find it more important to successfully explain our points of view and reach an understanding. Agreement is the "destination", if you want to use a silly metaphor.
But according to your logic, if we already agree and don't need a discussion to realise it, then our viewpoints must not be worth holding in the first place, because "What's the point of having a view, if the discussion used to get there has no significance?" That makes no sense to me.
Experience is always important, it can harm or heal you. Anything that will affect you, be it a choice or an action, is important.
Everything affects you, but some things affect you more than others, so some things are more important than others.
We still do not agree
Are you sure, baby?