I find, that a 'Zero Waste' or 'Sustainable' christmas means a reductionist way of thinking; and that perhaps it can come across repeatedly negative, and off putting for many.  No this, and don't do that.   And while it is true, it is encouraging minimising our consumption, of everything from energy, to christmas presents [though let's be real, did we really need all that stuff to begin with..].  But perhaps by having a more positive language, we might inspire more people to try?