Consider all human behavioral flaws. (A flaw being what isn't in our best interests, behavior which results in suffering in one form or another).
Where do these flaws stem from?
It's not complicated. Lack of knowledge or experience. I.e.ignorance.
If we knew better, we would avoid pain and suffering. It's as simple as not sticking your hand in fire.

Fear and Greed.
I believe all other flaws stem from fear and greed. One may argue that without fear people wouldn't be greedy but this site is not here to debate intricate behaviorist psychology or philosophy.
Consider some behavioral flaws, all of which cause suffering: Jealousy, insecurity, prejudice, stress, guilt(more on this below), anger, over-indulgence, drug-dependence, crime or hatred.
Think about each one and you will soon see that they all stem from fear or greed.
People are afraid of pain or loss and they are greedy for more of just about anything they desire..

So quite simply, to overcome all these negative behaviors which cause suffering we only need to address fear and greed. If you can accept that fear and greed are mistakes, then you can start to learn why we make these mistakes and how we can reduce our ignorance to avoid them.

Example: I don't think it's a great transcendent or intellectual leap in sentient beings with the intelligence which we posses to realise we are all unique with strengths and weakness, flaws and gifts, that we can all be pleased with who we are.... Children have that sense of self. Then quite simply, feeling insecure becomes redundant.

A thinking being questions everything.
I cannot reiterate this enough. Yes, I was one of those "but why?" children.
Sheep and robots simply plod along doing as they are instructed or as they see others do.
One of the biggest problems is that we become apathetic about why we live the way we do and why we behave the way we do. We look around us at how others behave and that apathy is reinforced.

During early childhood development the majority of our personality is made up. What we learned then is pretty much who we are today.
Do you agree with what you all were taught as a child?
Do you, for example, agree that constantly feeling guilt is a productive way for us to live?
Do you agree with what you were taught was right and wrong?
Were you conditioned with certain prejudices, taught to live in fear, worry or stress?
How much did you learn about why we are here, where we came from or where we are going?

Guilt, being remorse caused by feeling responsible for some offence, is a pretty disgusting feeling to be teaching our children. Apart from causing a myriad of other behavioral problems like self loathing which can entirely stifle one's quality of life, there is no practical use in it!
If a mistake has been made (and we are assuming that an 'offence' was a mistake), then we aught to fix it and avoid repeating it.
Again, pretty simple stuff. Logical. Fix the problem, move on. No point in suffering on top of and beyond the original problem.

Patriotism. Bound to turn a few heads... I don't mean healthy pride in one's culture. I mean the single-minded, ignorant, arrogant love of country over others. The thinking that you are better than another because of your country. Now I could write an entire essay on the futility and danger of fanatic patriotism.
Patriotism is defined as; Love of country and willingness to sacrifice for it.
Does this seem right to you?
In this day and age (of contracting borders, the internet, a shrinking world and cultures being merged in multi-cultural relationships) does blind overbearing 'puffed out chests' pride really have a place in our world?
Patriotism is the stuff wars are made of!
Again, I'm sure a lot of the value of patriotism was instilled upon us at a young age, probably with the best, albeit 'out dated' intentions. I simply suggest you don't blindly accept this concept as natural or fact.
Call me a world citizen please!

Not loving oneself is likely one of the most fundamental causes of pain and suffering in human lives.
It is also something we are strongly conditioned NOT to do!
Naturally and perhaps rightly, we are taught not to be arrogant or have inflated perceptions of self-importance (this is especially true when such feelings ever result in one thinking oneself better than others).
Now people get confused very easily here. Pride or ego is confused with healthy natural self-love.
We are falsely taught from an early age not to be vain, 'don't boast', 'don't brag', '...oh he loves himself' (as a harsh criticism), and so on.
Wrong!
We should encourage our children to love themselves and how to love themselves. Just as well we aught to praise and encourage our friends, family and indeed everyone we meet to love themselves.

A vengeful God.
This is utter blasphemy. Many religions with narrow perspectives and ones who wish to instill fear on the masses (how truly evil), teach that God is to be feared and that God is vengeful.
Look in your heart, look at parents, look to nature and see how utterly ridiculous this notion is.
Not only are these notions so utterly devoid of sense and truth, but they completely counteract their intent. That is, if we assume they are meant as warnings from would-be-sinners. Since all you are then doing, is scaring people into 'right-action' rather than have them learn out of experience and choose right action for their own good.
I wonder how healthy it is to teach children, on top of all the fears they already have to contend with, that they must now fear the almighty also...
I have nothing further to add on this subject since I don't want this site to be here as a spiritual discourse.
All that I am writing her seeks to come from logical observation of the nature of life.

In 'The Victims' section I ask if the masses even know what effect child abuse has on the victim, those they live with and society itself.
Everyone really needs to think about this because you all know several people who were grossly abused as children. 1 in 4!
9 times out of 10, the victims will not have the same chance to have fulfilling relationships as us more fortunate ones. Some parts of life, innocence, love, beauty, trust and so forth, will forever be lost to the victims. A great many go on to lead terrible lives following cycles of abuse. This is a tragedy worse than I care to dwell on.
It doesn't stop there. The actions of one ignorant animal now translate across and down the line from the victim. Victims will taint their relationships because what has been stolen from them. The victims children will be effected (and sadly often abused) and so on.
I'm sure you can put two and two together and see that what effects children and families effects society also.

The same problems exist when men abuse women, or anyone hurts another.

In the long run the damage from one act effects an eternity. It's like a domino effect I'd rather not get into details about. I'm sure, on some level, we have all dealt with people who hurt us only because they themselves have become damaged by some 3rd party.

This subject also begs a whole essay or book, but I just want to make it clear that this problem is FAR FAR bigger than you probably realise and stopping it, or at least reducing it is in everyone's interests and has to begin somewhere. If you see a child who looks like they are abused, talk to someone. Tell people the shocking 1 to 4 statistic, talk about it. Try to get schools to teach children about abuse. Education will aid prevention.