I have a couple thoughts here, in seemingly random order...
1. Enjoyment does not require laughter. I believe in training because [on the whole] aikido is something we enjoy.
2. Laughter is a mixture of emotions and can present itself in a variety of emotional states. Laughter is not necessarily enjoyment.
The martial arts instructor's desperate exhortation, "Don't laugh; this is a matter of life and death," is wrong on two counts. First, it probably isn't a matter of life and death, and second, even if it were there would be no shame in laughing about it.
While training, we [often] laugh for a variety of reasons, unexpected accomplishment, simplicity of our stupidity, humor, frustration or enjoyment to say a few. In aikido, we sometimes also use silliness to hide our inabilities. Ever train with the goofball that couldn't do anything right? Is he really so inept that he trips over his feet or is he simply struggling with waza and wishes to hide his problems? Often, I think instructors are trying to solicit an earnest response from students by simplifying the communication and interaction between partners. This is one of the better arguments I have heard for silence during training. More importantly, he may be implying that the particular waza should
require sufficient focus and attention as to curtail non-related behavior.
Remember your first date, when you kissed after a nervous laugh? The anxious chuckle when the doctor frowns while looking at your MRI? What about the hysterical laugh at the funeral? We laugh as much during anxious or nervous situations and during other situations. Know why those vets are joking? They are coping with an incredibly anxious state of being, often one civs cannot comprehend. I believe a lot of laughter on the mat is the outward expression of anxiety and nervousness. The inability to stop such behavior may be more telling than you think...
We've established, then, that strict solemnity makes us neither safer nor more skillful, at least so long as we aren't frivolously wasting time. Why, then, do so many martial arts instructors expect their students to act like Trappist monks at Mass?
Well, not really. You have made a case that solemnity makes training less enjoyable. This may be so for some, not for others. I expect my students to get it right. If they can do it with a joke and a smile, great. If they need to hunker down for a few minutes to get it right that's great, too.
The social nature of aikido makes for a tough spot here. We are intimate because we give our bodies to each other and that creates a social bond. Sometimes we forget that what we are doing on the mat is more important than the punchline of a joke. In a way, this reminds me of a seminar I attended during which the students were practicing a very common waza shown by the instructor, but they were practicing it as they knew it (not the way sensei showed). He stopped class and said, "you people just paid me money to teach aikido. We have spend x minutes on this technique and you are still not doing what I am doing. If you want to do this the way you do it, don't come to the seminar and save yourself money."
Matt- know I came across as a grumpy old guy in this post. Please dial down the harsh meter for me because I appreciate the honesty of the post