Much of how humans communicate with one another are with symbols. Words are symbols. Gestures are symbols. Body language is wrapped in symbols. Actions as well. Many of these symbols are encoded. Few of them are ever described to anyone else. The symbolic meanings behind such things are simply assumed to be shared by everyone. Unfortunately, they rarely are.
I might use neglecting-the-dishes or wearing-no-hat as coded behavior for disrespect. You might see it as too insignificant to symbolically represent anything. Or you might simply see that it means I'm a busy person. This is why so many misunderstandings happen so often. We use an encoded language of behavior, tone, and body language where everything is wrapped in meaning and where little checking is ever done to see if the message you've sent and the one I've received is one and the same.
One interesting cause for conflict is when these misunderstandings happen. Culture clashes, gendered expectations, and romantic misunderstandings are all the most obvious conflicts that can come from this. However, such conflicts can also be more subtle and long-lasting. Such as when two romantically interested individuals consistently misinterpret or ignore the other person's flirtations. Passive aggressive acts and things that are never actually said but assumed on the part of one or more people can also lend a heavier weight to your character interactions.