Re: Bowing in aikido
Discipline is necessary in martial arts training for the same reason it's necessary in the army. Somebody who cannot tolerate it will not be able to refrain from using the lethal skills they have learned in the dojo when circumstances do not call for it. Not to mention the fact that you just cannot teach a group of people who are rowdy and unfocussed. And when you think of your instructor as just a nice dude, you will be more tempted not to pay attention to his teaching.
In our school, we have to bow from seiza every time Sensei is done demonstrating a technique, and to say: Arigato! Then, we can get on our feet and start practicing.
This doesn't seem to get into Sensei's head, and he is always pleased to exchange a few jokes after class before leaving.
If you want to learn something, bowing seems to be only a very minor inconvenience to deal with.