welcome to my world. I try to be as conscious as I can about my environmental impact. At least minimalising it where I can. Like trying to avoid single use cups, or if I do use a takeaway cup I would never accept one if its Styrofoam (Also known as polystyrene). If you use this and dont know how bad it is. Just google "why Styrofoam is bad" and you can decide how you feel.
People buying bottled water for regular consumption is another big pet peeve of mine.
"The story of stuff" series is really good at explaining how bad certain "stuff" is.
http://www.youtube.com/watch?v=Se12y9hSOM0&feature=c4-overview-vl&list=PL77CE8943362CB9B0 is the story of bottled water, and a good way to see how bad it is, in a way that even a 10 year old could easily understand.
And for me the real ninja of the enviromental hurting world is "Palm oil"
http://www.saynotopalmoil.com/ (or just google why palm oil is bad and choose your own source). But so many of the stuff in the supermarket contains palm oil, and the vast majority of the worlds palm oil is grown in countrys like indonesia where rainforrest and such and being logged and destroyed in acres per day...and this is killing off rhinos/tigers/orangutan/etc etc.
Like if you eat
"Mars Incorporated ~ Click here for more brands
-M&Ms
-Snickers
-Mars bars
-Milky Way
-Twix
-Bounty
-Maltesers
-Doublemint
-Dove
Wrigley's (owned by Mars)
-5 gum (AP)
-Extra gum (AP)
-Juicy Fruit gum (AP)
-Starburst lollies
-Skittles lollies
-Hubba Bubba bubble gum (AP)
-P.K. chewing gum (AP)"
Then you are choosing to kill these guys

And really thats just a brief look at terrible things most people do every day.