But (and I realize I'm not saying this very well) what makes it "intimidation"?
That tango takes two, and sometimes there's a choice about whether you want to dance. The guy that eyed you and then cut you off on the highway is playing a game that he wants to play; it's called "I show you who's boss of this road", and he believes he can win at it. Maybe he's wrong; maybe you and your car can win. Maybe you choose not to play, but instead just shrug and let him have the lane. Can someone beat you at a game you're not playing?
I realize that the choice to not play doesn't always exist. On the other hand, you know that saying about when your only tool is a hammer, every problem has to be a nail. When someone asks "is aikido good for self-defense?" we know what they're asking - if we're not being disingenuous, we know that they mean as a physical response to a physical attack, not using ki to redirect the bad energy at the DMV. So we enter into that discussion, but in so doing, we need to remind ourselves that this is a tiny slice of self-defense. If you want to defend yourself, you'll use many more tools than just the physical responses of aikido - and that, to be honest, those are probably the last tools you should ever use.
Sure. But, while I can see how self-defense measures can lead to a sense of empowerment, when taken past a certain point, the measures themselves have a deleterious effect on a person's quality of life. You mention arachnophobia - as it happens, I have a very good friend who has a completely outsized freakout factor with insects of all kinds. This leads to behaviors such as drenching herself with deet, throwing out everything in her pantry and spending days bleaching every surface if she ever sees a grain moth, not wanting to visit my house which is out in the country and surrounded by gardens where I encourage some types of beneficial insects, etc. I keep my mouth firmly shut on the topic, but I see another choice: to attempt to address the fear itself, rather than to try to eliminate everything that provokes it from one's life.
There's a quote from Pema Chodron that I think is really relevant here, where she's talking about Shantideva's teachings about how we respond to the difficulties of life in the most counterproductive way. You can watch it on Youtube at http://www.youtube.com/watch?v=buTrsK_ZkvA
It's not to say that the problems on the outside aren't real. Generally they are (although this quote is a great example of how we tend to magnify them). But our ability to control these outside problems is limited. So, the choices are, as I see it: 1)Respond to the "provocations" of life's daily problems as if to an aggressive, conscious threat or attack on your self (which indeed they may very well not be...the guy who cut you off may be distracted or may have just seen his exit; the insect is simply trying to live), 2)Try to "cover the world with leather", by eliminating all the insects and bad drivers and people standing in line in front of you at the DMV (which of course you can't do), or 3)Respond to threats that really are threats, and "wear shoes" when dealing with the stuff that's just life being life.