I have been doing this Dew Challenge for the past two days, and I wanted to write down my initial thoughts.
First of all, I noticed right away a feeling of liberation. Some people might think that having the soda can in front of you all the time would merely serve to add unnecessary suffering to an already difficult exercise (that of curbing an "addiction"). Maybe for some that would be true. But for me it is a mental thing. Because I've decided not to drink the can of Mountain Dew, I now have motivation that I didn't have before when wanting to resist it. Had I simply said, I want to drink less, and tried not to think about it, it would have been harder for me.
Also, the point of the exercise is to use something relatively innocuous, like soda, to practice resisting urges. I need it to be difficult in order for it to be effective, but I probably would not recommend a similar exercise to someone with tendencies toward more destructive substances, unless they first proved to be capable with an easier challenge. As for achieving my own desired ends, Challenge itself provides the motivation I need to succeed with it.
So, back to the liberation. Obviously, one's feelings toward this challenge would be contingent upon their success with it. My first day was quite successful. I felt the urge to drink the soda many times in the day, and resisted every time. It gave me a sense of power and control over myself that is invigorating. I have realized that the benefit of this challenge is not only in the ability to say no to something you might want, but in the broader ability to decide for yourself and separate that decision from mere impulses. And isn't that what most of us want? We want to decide to exercise even when our momentary feelings say we don't really want to. We want to do things we normally wouldn't because of temporary emotions, and we want to avoid doing things we normally would do because of temporary impulses. This is not just about saying "no." It is about taking control, and I think it is exciting, even if the idea is a little silly on the surface.