It’s all about how they teach. In my case it needs to be not too easy for my own level and I like a challenge sometimes. They believe in my potential and are easy to relate with, passionate about their vocation and inspired thought.
The important aspects are also defined by what makes a teacher not helpful; if I know the person hates me and especially if it’s based on my ethnic roots and/or diagnoses I feel differently and think more for myself than listening to empty words and judgement based on stereotypical views.