When a passenger is behaving badly on a bus or a plane, it can make for a very unpleasant and uncomfortable ride.

I was the second person to get on the bus. When the driver saw that I was struggling with my bag and suitcase, he took the bag and put it on floor of one of the front seats.

I was so tired, I practically collapsed into the seat. As I settled into the seat, I heard a voice say, I sit there, I sit there. I didn’t turn around. I sit here, she said again. When I looked around, I noticed a woman — I couldn’t tell her age — standing just behind the row I was sitting and pointing to the seat next to me, the seat where my bag was.

I sit there, she continued.

I looked at her, looked at the seat and looked back at her again thinking, find another seat. There were at least 30 empty, none was assigned. As exhausted as I was, there was no way I was getting up. I didn’t care that she was mentally challenged.

I sit here, she repeated, like a mantra.

An elderly woman who had followed her on to the bus pleaded with her to quiet down. You can sit here, she said, of the empty seat next to her.

No, I sit here. F U!

Calm down, Angie. I’m going to call Frank. Do you want me to call Frank?

But Angie wouldn’t be calm. Instead, she started hitting the back of the seat next to me. F U, A-hole!

I sit here.

What did she say? The driver asked, looking in my direction.

I shrugged.

She was quiet as the bus pulled out but it didn’t last.

I sit here, she resumed.

Just before we got to the first stop, she got up and stood in the aisle.

I’m going to hit you, she said to no one in particular. I watched her from the corner of my eye. If she hit me, I was going to hit her back and call the police.

As the bus pulled into the stop, she jumped off. A-hole, she said.

I’m sorry, her companion said as she passed me. I have no control over her sometimes.

I understand, I said.

The driver, too, apologized.

Luckily, this person did not become physically abusive. Last week, for no reason, a passenger shot two people on a New York city bus.

Have you ever witnessed a passenger acting badly on a plane or bus? How was the situation resolved? What would you do if the person sitting next to you was behaving badly?