These are the people who don't take courtesy and respect with them while travelling. Due to such behaviour, many have to travel uncomfortably, sometimes even unsafely.
Facebook and Instagram page, Passenger Shaming is a cause to deal with exactly that.
Here's what people have gone through.
My sympathies to the co-passenger.
Both can have a good time.
That which is not supposed to be.
And certainly that person needs to understand it.