I rejected a gift that came in an Amazon box.
Very politely, and apologetically., I said, "I'm really sorry, but I can't accept this." And why, (working conditions, monopoly etc).
It had an effect not only on myself - to make an ideological whimsy into a real and binding action - putting my skin in the game - but also on the other person who was initially embarrassed, then emboldened. It led to a memorable and positive conversation.