I believe words are not only powerful, they can be very seductive.
Consider the following words: "can't, must, musn't, ought, should, shouldn't."
Now these ones: "can, could, may, might."
I find the first list tends to disempower and limit; while the second list empowers and gives one the freedom to choose.
When I disempower or limit someone with my words, I am doing the same to myself. When I give someone the freedom to choose, I am freeing myself.
Word to the wise: I never do anything just because someone believes I should.
Related articles: Switch It Off!; Model Behaviour; I am the Answer; Words are Alive; Everyone?; I Think I Can; Tuning Out the Collective Consciousness; Freedom of Expression - Revisited