There's two broad categories of discipline styles, which I think of as tough love and compassionate nurturing. Both have their uses. For example, I've seen some students thrive under teachers with a challenging, aggressive style. These students respect their teacher's no-nonsense attitude and like direct, straight to the point feedback. They may also have a thick skin or a wicked sense of humor. Other students wilt in such high-pressure lessons. They need a reassuring, compassionate teacher who patiently explains and demonstrates for them, giving gentle feedback. Teachers who only use tough love might drive away sensitive students, maybe even blaming the students themselves for not responding properly to their methods. On the other hand, students who crave tough love might find themselves dissatisfied and frustrated with gentle, nurturing teacher--they might refuse to practice or follow instructions. Indeed, some students might need both compassion and tough love from a teacher, depending on what mood or situation they're in. So how can we know what students need form us at any given moment?
First, consider the student. Are they active and brash, or quiet and reserved? Do they seem reluctant or impatient? Once you have a good idea of their personality (and it may take several lessons to figure them out), consider the circumstances. Even an ordinarily tough kid might have a stressful or difficult day once in a while, where they might need some compassionate encouragement. I try to be especially sensitive before and after performances--even brash students get nervous before they go on stage. Other times, a normally quiet student might start acting disrespectful or difficult (particularly if they're tired or stressed), and might need a little tough love.
Teachers may feel more comfortable using one method more than another. Early in my career, I found myself using the same harsh, high-pressure approach I'd endured with all my students. Many of my students frequently broke down in tears, just as I had in my lessons. I realized that I couldn't bear the idea of treating children that way anymore, so I took a class in Suzuki Method and worked hard to become a loving, compassionate teacher. Yet, I sometimes have students ask me to be tough on them, or push them hard to succeed. For those students and a few others, I'll break out the tough love, but I'm glad that's not the only tool I have to work with.