The ups and downs of Cambodia

I'm really loving Cambodia, from the history to the sights and people. The only negative thing I have to say is that the hassling and begging is the worst of all the SE Asian countries that I've been to thus far. I feel very torn about it.
Part of me wants to help everyone and every cause. Part of me wants to be left alone so I can read my book on the beach in peace.
Ok, let me back up a bit and explain what it is I'm dealing with here. Every day and in every town (except the home stay) I am continually approached by children or handicapped individuals selling bracelets, books, DVDs, anything. I am continually approached by children and handicapped individuals begging or singing and begging or playing music and begging. When you do finally break down and buy a dollar bracelet from one kid they all come running and swarm around. Tuk tuk drivers, people selling tours, people selling rooms, people selling themselves, it's constant. When I'm eating, reading on the beach, walking down the street it's "hey lady I got cold water, you want?" from 20 feet away.
It's draining having to say no, no thank you, not to today, no I don't need whatever it is you're selling over and over. I feel like a broken record, put on repeat with a false smile plastered on my face. Meanwhile inside my heart twists in empathy and a deep desire to help in anyway possible. Especially when it comes to the kids. How can you say no 50 times to a 5 year old that you know should be in bed because it's 10pm on a Tuesday night and instead she's carrying around a basket of bracelets to sell instead of being at home finishing her homework? Stab. Guilt. Or the man missing several extremities that he probably lost from a land-mine that was placed by the USA during the Vietnam War? Go USA! Not. Stab. Guilt. Or the 18 year old hookers lining the streets or the woman holding her infant asking for money, etc... This is an everyday multiple time a day occurrence.
My other tactic for dealing with this is to ignore them entirely and not look up or say anything. Which just brings on a whole other side of guilt. Or when I think unkind things because I just want to eat my meal in peace, not have a beggar and his child asking for a donation while I stuff my face. Again, the guilt! I could be catholic with all this guilt!
Why don't I just give something you might be wondering? Sometimes I do, but they recommend not too. By buying bracelets from the kids on the beach reinforces it, keeps them there, and doesn't fix anything in the long term. It's better to give to an organization that is trying to help. The group has, in just about every town eaten, gotten massages, or shopped at places that support different organizations, which is the best of both worlds.
The point of my ranting? Cambodia is an amazing country, but has a dark history that is still hovering over like a storm cloud.