The Negative Effect of Nudges

Is there a point in which we get used to those nudges, and they are less effective? In the UK, I think it was- it was quite embarrassing to ask for a bag. But once you kind of get over that, well, it's fine now. You kind of then get used to the 5P. It's only 5P. Who cares? If I thought it was free,. We don't like paying for anything that we used to have a free.