To say that because a student crashed it is always the instructors fault is asinine. If you dont push the students abilities a little then they will never progress. Knowing just how far to push is the trick and I'm sorry but last time I checked instructors are human, judgement is not black and white, and students don't always give you the whole story. Flying is inherently dangerous, but fortunately it is usually only dangerous for the airplane when flying models. A real instructor will know the basics required to build a strong foundation for learning to fly. If you don't have a good understanding of the aerodynamic forces and how they affect flight than you will be doing a great disservice to your student. As Hossfly said there are drivers and there are flyers. Drivers know how their plane will react to different control inputs but are very reactive to outside forces. A flyer knows how airplanes react to their control inputs and outside forces such as wind, humidity, temperature, and the various forms of turbulence and are more proactive. If you are always ahead of the plane and you have a firm grasp on the basics of flight than you have the potential to be a good flight instructor. Give the student a solid foundation of aerodynamics, safe practices and risk management and they will have the best chance to succeed. If you are struggling, get help. No one was born knowing how to teach and sometimes you just don't mesh with a student no matter how good you are. Finally a good thing to always keep in mind is that students are trying to kill that airplane. While in reality it is not true, if you keep that thought in your head it will better prepare you for some of the wild, seemingly insane, things students due in the course of their training.