It's less how the teacher <em>speaks</em> to me, and more how the teacher <em>views</em> me.
If a teacher views me with contempt / sees me as stupid but pretends to be nice, I'm not going to like that teacher. If the teacher is strict but fair and doesn't view me poorly, then I would like that teacher. But I'd avoid a strict teacher who sees me as inferior, and choose a kind teacher who is sincerely friendly.
It all boils down to their attitude and sincerity.