Re: Mistakes that taught you a lesson for life!
In response to Graham's bowing example, why are people assuming the instructor has an ego problem? The assumption itself shows ego.
Parts of martial training include presence and attention to detail. Customs and etiquette may vary from dojo to dojo: you may bow a certain way, shake hands, salute, stand on your head, or do the chicken dance---who knows---but, it's generally clear when a practitioner is not fully present when doing whatever it is you do. Waking up to that is part of training.