Sorry, empathy, but no sympathy from me; parking in any big crowded city is usually high. San Francisco is so expensive, that when I lived there a few years ago, the cost of insurance and parking both at home and at work (neither came along with the rent or job offer) was prohibative enough to keep me from having a car there. The same goes for tourists; this charge is just part of the landscape.
Tips for the future: Either find a cheap place to put your car (if you absolutely have to have one), or forgo the car and use the public transit. It's not a coincidence that cities with high parking rates usually have great mass transit systems (New York, San Francisco, Chicago all come to mind).
If you do some homework, you can find options to park. However, DON'T expect to find such deals on Nob Hill, Times Square, The Loop, etc. Options are (in order) SOMA (although that's getting scarce), an obscure garage on a sidestreet in Manhattan (I've found them for as cheap as $10 per night), etc. In any case, you'll need to get to and from your car, either with a cab, walking, or again, public transit.
Unfortunately, parking (free, cheap, or otherwise) is only a "given" in wide-open spaces cities, where land is not at such a premium. If you choose to do the public transit option, you're in good company; as a hotel manager (in all of the mentioned cities) I can assure you that most guests are aware of the parking expense and hassles, and do choose to take cabs or the mass transit options. For many of these people, this is viewed as part of the local color, as most residents use it as well (as opposed to the cheap/free parking cities, where public transit is sometimes unsavory). However, mass transit in these cities is exceptionally cheap, safe, and generally a lot FASTER than the car. Plus, where to you expect to park once you get to your destination? You'll go nuts trying to feed meters (if you can find them), avoid the metermaids, potential car thiefs, etc.
The American notion of the nuclear family with two/three/four cars, plentiful free parking, cheap gas, etc. (I grew up in a city where this is the norm) is simply not valid in many cities, and the trend is getting worse; now "secondary cities" like St. Louis, Cleveland, etc. are going that way.
One interesting point: Some hotels in "cheap parking zones" consider placing the parking gates/attendants to repel would be car thieves, purse snatchers, and the like, just because the delay of the parking booth presents a barrier to the quick getaway. (I know this isn't relevant to your point, but thought I'd throw that in).
Finally, I spent a night at the New York Hilton a few years back; the room was comped, but the parking was almost $50! I was similarly put out, but I paid it, as I didn't have the time to prepare for an alternative, nor to search around for one. I hope that my car slept as well as I did!