Yup, auctions are unreliable if you want to buy, that's for sure. For what it's worth though, if you stick with them you can average out on the positive side. Yes, that Civic sold for twice what it was worth, but I have also scored stuff like an '82 Chev shortbox pickup, 2wd, healthy small block, chopped roof, shaved door handles, frenched antenna and 32 Ford tail lights for $1400. It all depends on who is there, the weather (yes that plays a big role, if it's crappy out less people show up and you get better deals), the time of year, etc. They are kind of a commitment - if you want to take advantage of them you have to go to a lot of them. It's like anything else, practice practice practice. But whatever you do, don't think it's like those auction shows on TV where people roll in and score a bunch of good loot super cheap. There are 300 other people there expecting the same thing! Do your research, pick your price, and walk away when it goes over your price.
Edit: Haven't had a chance to watch the above post, but I will. Auctions bring out the crazy in people lol.