There is a saying in budo, or "Everything begins and ends with respect" (礼に始まり礼に終わる). Last night we hosted an outside teacher from another country. The thing which made me the happiest was how polite our students were. Everyone treated each other with respect and everyone had a good time.
For the most part, the martial arts are physical and up to a point, anyone can become skilled. Reigi-saho or etiquette is one of those things which cannot be taught but can be learned.
Being a jerk reflects poorly on your teacher, your parents, your art, your dojo and most importantly you. Be careful what you say or do because it means a lot.