A leader in fact, someone with the ability to relate to a wide range of people on a variety of levels and topics. That agility must be an aspect of a Buddha's mind; in fact a requirement - in order to bring the Dhamma across to as many people as are capable of receiving it.
For those who knew him there must be a hundred stories about the character of Ajahn Chah: his willingness and ability to engage with a whole slew of people, some of whom - generals, owners of gambling clubs, simple-minded villagers, people looking for lucky charms - many of us would have written off as hopeless and not worth wasting time on. Yet he had the kindness and the skills to draw them towards the Dhamma. Other masters seem to approach things differently - Ajahn Mun for example tended to shun society and avoided, as if it were quicksand, settling into any monastery until the last seven years of his life. So one had to track him down to some remote forest dwelling to receive a teaching; and pretty soon he'd be off on his wanderings, without telling anyone where he was going. Yet it is from him that at least two generations of great forest masters have derived their inspiration and standards of practice. Elusive he might have been, but his accomplishments have given enormous vitality to the Sangha: where would we have been without him? Ajahn Lee, on the other hand, was one of the first of Ajahn Mun's disciples to come out of the forest; he established several monasteries, took lay people off on tudong, and gave hundreds of talks - some of them amongst the earliest Dhamma talks to be recorded on tape in Thailand. And there are many other masters, by turn humorous, remote, silent or highly articulate; part of the richness of the Dhamma inheritance is that it manifest through forms that, however purified, are still remarkably personal and idiosyncratic.
In a way this is a statement about what anatta (not-self) does not refer to - there is a citta that is the subjective core of the personality. Citta is not actually a thing, it is a process of sensitivity and response that modulates according to circumstances in accordance with inherited tendencies; it is changing from moment to moment. Anatta is the realisation that the citta is dependently arisen; that means it is not Self - not some isolated and independent, unchanging entity. Rejection of the citta as a process is at least as harmful as the assertion that it is a permanent thing.
So the issue of personality also makes a statement about the practice, and the expression of the Dhamma. Quite a few of the forest masters express their insights in terms that are doctrinally questionable - Ajahn Maha Bua refers to the "deathless citta" and Ajahn Thate had his own way of defining samadhi as distinct from jhana. Yet these are people who have given massive amounts of endeavour and commitment to the path of practice, and whose accomplishments are self-evident. Then there was Ajahn Buddhadasa whose swipes at Acariya Buddhagosa, the foundation stone of Theravada, are an embarrassment to the faint-hearted...then Ajahn Sumedho raises eyebrows in Buddhist circles by references to God....The Buddha's statement of teaching doesn't seem to allow much room: Bhikkhus, these two things conduce to the confusion and disappearance of True Dhamma....the wrong expression of its basic meaning and wrong interpretation of its significance (Anguttara Nikaya, Twos, 20).
Maybe when it comes down to practice, we have to allow that language can only offer basic meanings, the master has to indicate, within a framework of consistency of aims and means, which expression and approach works best for which individual. Direct practice means that the results can only be known in oneself. More precariously, it also means that in the process we have to fully be ourselves - in order to realise that our subjective core is not-Self. The classic tools of practice are calm and insight, but do we always use them to enter the core? Or just to change the form of the identity? Any experienced meditator will know how readily self-deception covers the changing citta; how strong is the desire to be Somebody Who is Enlightened; how in fact the most deeply-rooted hunger is not for sense-objects, but to have an unchanging, satisfied Self. Calm and even insight at a certain level, get enrolled in the mission to accumulate and bolster up the self-image. So the other renowned strategy of the tradition is one of "pushing your buttons": things seem settled and peaceful, so let's try a few weeks of tudong with little to eat, insecurity and some sickness; let's see what being in a noisy crowd of people asking pointless questions does to mindfulness. What's it like when the daily routines seem dreary, or the teacher doesn't come up with a talk that inspires us? What comes up out of the "enlightened heart" is: "This is ridiculous! I didn't come here to do this! Who does he/she think they are!" And a dawning recognition that the cosmetic job on the mind is starting to crack.
The tests and trials vary in terms of persons and situations; but you notice that the master is the one who doesn't get caught up in the drama. Sometimes that one is outside, sometimes within. Whichever way it is, the teaching is right there: with the revealing and acceptance of oneself as a prerequisite. Then it requires discipline to take hold of the self-process as phenomena that are dependently arisen; otherwise the practice turns into a personality cult - narcissism or hero-worship. It takes a pretty solid kind of person to know what they have - in order to know who they're not. It's a deeply personal thing.