Sometimes sustainability is choosing between food covered in plastic that is about to be thrown out versus the fresh and package-free vegetables on the other side of the grocery store. There’s no true winning sustainable option, because if you’ve picked the first option then you’re now supporting plastic covered perishables. On the other hand if you’ve picked the second option, then you’ve allowed perfectly fine food be wasted and tossed in the landfill, plastic and all.
Another example would be the much popularized use of soap nuts for our laundry in Western countries. Soap nuts don’t grow in the Western side of the world—they grow in India, and take a lot of effort to grow—but people here like using them because they’re safe to use, relatively cheap to us, and readily biodegradable unlike typical store bought laundry detergent. It’s a no brainer to use if we’re trying to be more environmentally conscious, but they pose much larger problems back in India. Popularized Western usage of soap nuts would mean more and more shipping from planes coming from halfway across the world. A huge carbon footprint for cheap, safe, clean laundry (there are more ways to clean laundry than one for that matter).