Good driving instructors should make the most of your lesson time. You should have their full-attention throughout the lesson, with no stops to pick up or drop off, fill-up with fuel or make phone calls. They shouldn’t shout or make you feel uncomfortable in any way, even if things go wrong.
Some driving Instructors work by themselves, while others are part of bigger driving schools. Whatever type of driving instructor you decide to go with, make sure you talk to them directly and not just their salesperson to make sure you like and feel comfortable with them.