Flying the unfriendly skies

I am writing this post at an elevation of 35,000 feet on a trip across the Pacific Ocean. The last month has provided many opportunities for me to fly, and I must admit I’ve been pleasantly surprised by the service provided by flight crews and agents. I am, however, disappointed by the lack of consideration offered by some travelers to each other.

On this very crowded flight a rather large gentleman boarded the plane with his wife, took his seat and proceeded to say goodbye to his spouse. She said that she would see him later as she went to another row in the rear of the plane. A very happy honeymoon couple was then placed next to him with absolutely no shoulder or legroom. If his wife could not sit comfortably next to him, how could perfect strangers do so during a five-hour flight? 

The gentleman proceeded to act disgusted that anyone was placed next to him. He maintained possession of the armrest and did not offer any empathy for the squished couple.

I know requiring large travelers to purchase two seats is a controversial discussion, but why should any other traveler be inconvenienced while, in this example, the wife is not even willing to be uncomfortable (knowing the space requirements of her husband)?

Should the airline have offered a solution?

Should the honeymoon couple have requested anything to change their situation?

What are the responsibilities of travelers with regard to mutual respect and consideration of others?

Anxious to hear your thoughts and comments.