Can you give me an example of a scenario where you don't know which or who is right or wrong?

Okay, so I need scenario or a problem where you don't know which side is right and which side is wrong. For example, you tell your friend she's not fat when the truth is she is. So just like that but I need a little deeper scenario. I need it for school to explain how one differs perception from others. :D Thankie. :*