Left and Right
Headphones usually have “R” and “L” written on them to indicate how to wear them. It’s not very dramatic if you wear them the other way around, but it can be somewhat uncomfortable. However, this happens to a lot of people when they’re using headphone models that are alien to them. This girl is oblivious to the fact that she’s wearing her headphones incorrectly.
Someone should probably tell her how to wear it correctly. They were labeled “L” and “R” for a reason, and the label is right there. How could you miss it? For some, it doesn’t matter, but for this guy sitting behind her on the plane, it clearly does. But if she’s enjoying her music in her oblivion, who are we to rain on her parade?