I believe that the words people use can have a major impact on the way that they think and behave. One good demonstration of this cause and effect considers the use of two subtly different contractions with important implications, don't and can't.
As the title of this post suggests, I find that in most cases the former is greater than the latter, as in better and more useful. Don't often implies a choice ("I don't smoke") or an order ("Don't touch the stove"). Can't, on the other hand, often implies a restriction, whether it be self-imposed ("I can't smoke") or a rule ("You can't touch the stove").
I like choices. I know a lot of people who like choices. I do not like rules. I do not know a lot of people who like rules. My intuition tells me people are more likely to rebel against things that they do not like than things that they do like. Thus, they are more likely to go against rules than choices.
I will acknowledge that it is easier said than done, but if you want to stop a bad habit for instance, try thinking and talking about it in terms of don't rather than can't. You may find it to be more effective.
