There are several causes for the problem discussed in this forum. One is the abusive behavior of the passenger and what may lead him to behave that way and the other are the seat space provided by Qatar Airways in their economic class cabins.
For the passenger, nothing can be done, except punishing his behavior.
For the ergonomics of the economic class seats, there are solutions in the market already used by genuine 5 star airlines, that would stop the occurrence of these complains.
Let’s take the example of Cathay Pacific – an airline the listens to their passengers and act upon their suggestions – they have recently refurnished their entire fleet with new seats. The economic class seats are embedded in a fixed shell. When reclining the seta, it moves within the shell and without disturbing the personal space of the passenger behind.
This sis how Cathay Pacific presents their innovation:

"The first thing you'll notice in our new Economy Class is that your space really is your space.
Every seat is designed to give you a protected space of your own.
Innovative fixed-back shell seat ensures your space is your space."
by Cathay Pacific (the truly 5 stars who does not need to remind its passengers of its grade!)

http://www.telegraph.co.uk/travel/destinations/asia/hongkong/4689103/Cat...

Let's take the example of Cathay Pacific; they introduced new seats, fit in a shell, so its movement won't disturb the passenger sitting in the back. Have a look:
http://www.cathaypacific.com/cpa/en_INTL/whatonboard/neweconomyclass
"The fixed-back shell seat in our new Economy Class ensures that no one in front of you will ever intrude into your space again. So you can relax and enjoy your 9" widescreen TV with StudioCX – featuring a rotating library of 100 movies, 350 TV shows, 888 music CDs, 22 radio channels, and entertainment programmes in nine languages."

Leaving the uncivilized behavior of certain passengers aside and the inability of Qatar Airways to walk their talk of % star airline, let’s see how Qatar Airways deals with their passengers’ suggestions / feedback:
In relation to the report I filed on 26 May 2009 (http://www.qatarliving.com/node/525557), regarding a similar incident, where security on board was at risk, they have never acknowledged the receiving of my report.
Two weeks later, I called their Customer Relations Department and after a few failed attempts, I got through and I was told that my report has been received and it was going to be processed soon.
Four weeks later, I still haven’t heard of anything from Qatar Airways again and I called again the same department. This time they told me, with any apology, that the person in charge has left on holidays and the case has not yet been addressed. They simply added that they will talk to their boss to transfer the case to another agent.
Incredible professional levels for a 5 star Customer Relations Department!
Let’s wait and see what or when they will answer.