Although I am not experienced enough in Aikido to instruct, my day job involves instruction. In that venue fear, intimidation, peer pressure, etc all reduce a students ability to grasp concepts and slow learning to a ridiculous degree. The best learning environment is one wherein the students stress level is minimized to whatever degree is possible.
I must respectfully disagree with the concept that all MA practice begins in fear, as no MA that I know of is a quick solution to physical threat. I began study out of a genuine interest, and stay due to a pull in my blood, not in response to threat of bodily harm.