Why do we Litter?

It seems to me that there isn't much we can control of late. The stock market is tumbling down, the economy isn't the greatest and people are fearful to spend. President Obama is working fervently to handle each issue - but our government is overwhelmed. I have a thought that I ponder quite often (okay daily) that if everyone cooperated with could solve an entire major issue overnight that is severly hurting our environent. Why do people litter? Why? - When it is so easy not to. Just think for a moment if you didn't litter what benefits could be gained - State workers wouldn't have to be on the roadsides backing up traffic, you would arrive happier and quicker to and fro, they could be doing more meaningful jobs like repairing our roads. Our oceans wouldn't be polluted and are eco system would be so much healthier. Recently, I went to Disney where we have travelled many times over the years. Every time I go there I am impressed with their garbage patrol. None - I simply can't find anything - not even a random cigarette butt. I look and search - but nothing. How do they do it? And should we consider hiring Disney as a special task force to clean up America? Or - Can't we simply do it ourselves. So I ask - Why do we litter?