One of the differences between Zen and so-called self-improvement practices (including mindfulness) is that Zen does not encourage its students to be more like the teacher or other members of the community, but to become more like one's true self. In this aspect, Zen is very different from a cult, and this was nicely illustrated in an exchange between Kodo Sawaki and his student Kosho Uchiyama.
Sawaki once said "What is the use of doing zazen? There is no use in doing zazen. Until this penetrates your thick skull and you are really doing zazen that is of no use, it is really of no use."
Sawaki (1880- 1965) was an unconventional and dynamic person, the very embodiment of the ancient Zen masters of legend. His parents died when he was very young, and he was raised by a professional gambler married to a former prostitute. At 20 years of age, he was drafted by the Japanese Army and did two tours of duty in the Russo-Japanese War (1900-1905), even though he was gravely wounded during his first tour.
According to Uchiyama, Sawaki was from birth a "vital and stimulating person who dominated other people and attracted them like a magnet. This was his karma, as natural for him as a cat catching mice or a musk deer emitting an attractive fragrance; it was not his greatness as a Buddhist." Uchiyama, on the other hand, describes himself as such a fainthearted person that he hesitated to tell people that he was Sawaki's student.
In 1941, when Uchiyama became a monk, he asked Sawaki, "If I study under you and practice zazen for as long as you are able to teach, can I become a stronger person?"
Sawaki immediately replied, "No, you can't, no matter how hard you try. I did not become the person I am because of zazen. By nature I am this way. I haven't changed since my youth."
But Uchiyama thought his teacher was just saying that so as to avoid future disappointment, but that if he practiced hard and long enough, he, too, could become a stronger person. But Uchiyama, who eventually became a significant Zen teacher himself, later noted, "I now understand that there is no use in doing zazen. I am still a coward and never became even a little like Sawaki Roshi. A violet blossoms as a violet and a rose blooms as a rose. For violets, there is no need to produce rose blossoms."