Most likely culture!  American are raised on beef and its ingrained in us from babies...

I walk pretty much everywhere that I go which reduces carbon emissions. I also don't eat meat/animal products which helps protect the environment, animals, and reduce carbon emissions. 

This year I have focused on reducing my use of single use items by stashing grocery bags in my back pack and car, meal prepping and bringing real silverware and a cloth napkin, saying no to the straw, and only getting a coffee if I have a reusable cup with me. I could be better about actually bringing the reusable grocery bag in and using it. I will challenge myself to either carry my items or go out and get my bags before checking out if I forgot them in the car. 
I love the idea of bringing your own containers for leftovers from restaurants! I did that while traveling in Cambodia a couple years ago but then didn't bring the habit back home. I will place a reusable to-go container in my car for these situations. 

I think that creativity plays a role in practicing simplicity because you have to think outside of the box to make what you do have work. I grew up very poor and my mom was always very good about this, especially when it came to meals. She created great meals out of very little.
I think that creativity also plays part in challenging the instant gratification mindset that many American's have by asking us to slow-down and think, envision, dream before rushing to the store. 

I love shopping at the farmers market or local farm stands. But these options are not available during winter and early spring (October - April/May). To combat this challenge, I stock up on things that store well like winter squash, potatoes, onions, carrots, and dried goods such as dried beans and oats. I also try to preserve as much of the fresh harvest as possible. Canned tomatoes and fruits are a must! Right now, I have been going out on the weekends to forage for wild mushrooms, which I sauté and freeze.