Gandhi's "become the change you wish to see in the world" is unfortunately one of those horribly misapplied items that is circulated with wild abandonment by some people who feel they've suddenly been struck with enlightenment. The idea nevertheless is a good one provided one understands what it really means and where the phrase really has relevance. Below is one such instance.
You may know the delightful story about the mother who went to Gandhi to get him to ask her boy to stop eating sweets (the kid wasn't listening to her apparently and she figured she'd bring in the big guns!). Gandhi said he would but asked her to come back in 2 weeks. When she did, he told the kid to stop eating sweets with some rationale for doing so. Awestruck by the great Mahatma, the boy readily agreed!
The mother was puzzled though and asked Gandhi why he didn't just talk to her boy two weeks ago.
Gandhi acknowledged with some embarrassment that he would have, but before he could legitimately ask another to do so, he first had to shake his own 'sugar habit'.
If eating sugar sweets isn't healthy, one shouldn't do it. Gandhi's conscience evidently came to his rescue since he had to face that little boy!