Recycling
In Thailand, there's a group of people who traditionally 'scavenge' in rubbish bins to find anything that can be recycled, and sell it on for profit. So, even if you don't recycle yourself, these people do it on your behalf anyway. It's a pretty nasty job, as it involves digging around your bins to find anything useful among all the grimey stuff. A friend suggested (thanks Ellie!) a kind way to treat these people - why not separate your recyclable stuff already, before throwing away the bags? This saves them from digging through nasty remains of food, and at the same time makes you more conscious of what you are using...