When people don't understand each other, it causes misunderstandings.
Misunderstandings can cause problems between people.
Examples:
There were many misunderstandings between them.
Misunderstandings can make people sad.
The misunderstandings between them made them stop talking to each other.
The misunderstandings about the plan made everyone confused.
The misunderstandings between the two countries almost caused a war.
The misunderstandings in the story made it very funny.