Don't worry about it. It's a taken of my appreciation for your business, and friendship.
没关系的。这是向你表示我们在生意及友谊上的一点心意。
feel that they have not received adequate treatment unless they are able to carry home with them some tangible remedy in the shape of a bottle of medicine,
觉得没算得到充分的治疗,如果不能带回一些看得见、摸得着的药物回家的话,如一瓶药水、