Representing Reality Versus Interesting Plot

I've been working on my novella for the past week, and I've made some decent progress (not quite up to my goal, but still I've got some new pages), but I'm struggling with how to motivate my characters' actions. I was reading a writing book recently that commented on how we can always figure out what a character would do in a situation by imagining ourselves in that situation, but I think that's not very good advice. Most of the time, what I would do in a situation would be the most reasonable thing, which is probably not at all interesting.

So I've been working on a scene where two characters are having an argument, and this is really giving me trouble because I don't really know how people have arguments in real life. If I try to imagine what I would do in the situation, I come up with my characters sitting down together and reasonably hashing out their differences so they understand where each other is coming from and see how they misunderstood one another, and then they make up. But that's not interesting for a story. There's no drama there, no tension. But I can't really see why anybody would yell and scream and throw things or whatever. That's ridiculous behavior. There's no way for that to come across as realistic, at least not to me. I don't think I've ever yelled at another person in real life.

But in order to move a story forward in an interesting way, in order to increase the tension, there needs to be conflict. But conflict seems to me to usually be unrealistic. Most of life is not made up of conflict. But most of life is also boring and not worth writing a story about. But if I increase the conflict, the whole thing starts to feel contrived or sentimental, like I'm stretching to come up with something because that thing is interesting rather than because it organically evolves from the situation and the characters. But if I play down the conflict to a more realistic level, the story feels boring or frigid. There must be a very fine balance, but I struggle to find it.

Ultimately, what I want to do with my fiction is to say something about the world, to represent how things actually are. But I also want to write something that's interesting to read. And sometimes those two goals seem to be mutually exclusive.