> Chances are, within most of our lifetimes, the technology will be
>manifested to such a state in which we can select our emotions to a certain
But this is possible already, without drugs or nanotech or genetic engineering. Why would anyone opt for the technological approach to something like this when you have no idea of the side-effects? Cognitive psych has been studying this very thing for 30 years or more, with the advantage that if the emotion you don't like actually serves a purpose (and it usually does, if you take the time to learn what it is), that you can develop an alternative mechanism to address that need.
Just because Prozac or Instant Smile or whatever doesn't make you feel intoxicated, it doesn't mean your problems won't still be there when you come down.
> Personally, I would opt to exorcise any trace of fear or anxiety.
*Any* trace? What about the fear of driving too fast? Or of the guy with a knife demanding your money?
May I suggest that the emotions we dislike aren't emotions about primary experience, but emotions about emotions. We feel fear, but we get agitated about feeling that fear because just now it might hurt our performance of a particular, important task, like making a speech or standing up to the office bully. The original emotion almost always serves a purpose -- in these cases, it gets your heart rate up and sharpens your senses, both of which can be useful. But when we try to stanch the emotion we create an internal conflict that blocks our mentation. I'd suggest that what you're after is full, congruent emotion -- flow, it's been called, among other things -- so that your meta-emotions function in line with your primary emotions. It's a simple matter, though not always an easy one, to program in this adjustment.
It seems to me that we have so many undeveloped resources at our disposal already that much of the time finding a technological means to effect change just hides a lack of willpower. People can multiply huge numbers in their head; people can control their heart rate; people can view remote locations; people can cure themselves of cancer. These and hundreds of other examples are documented extensively. On a more mundane level, people can edit their emotional palette, "sell ice boxes to eskimos" (sorry), learn multiple languages at any stage in their life, and so on.
To date, what we haven't as a species been able to do is to learn to do things like this without a change in lifestyle, and I think that's the allure of technology. We can stay the same old slobs and also live to be a hundred. But I wouldn't have thought this had much to do with extropianism.