I can't and won't make that claim. But the longer I collect, the more familiar I am with the hobby. Occasionally I will take a chance, but more often then not, I'm much more careful these days.
I like your open-mindedness with regards to the replies here. Many times I've seen people post a coin asking whether or not it was fake, and get upset at those that break the bad news to them and refuse to believe it. Good to see that this became a learning experience for you.
Well I have been fooled. Spent about $300 on a Julius Nepos AE4 monogram. Got an opinion from Raziel, and he reckoned it was a tooled Libius Severus (the monograms are similar). It would have been worth $300 or more as an untooled Libius, but in its vandalised state is worthless. Anything in my collection now that is worth more than a couple of hundred dollars, I have thoroughly vetted and scrutinised. I'm reasonably confident about what I have, but there's reasonable doubt.
I know what you mean, I've seen people respond that way too, when they are let down by the fact that their coin is a fake. But I truly love collecting coins and the history it teaches us. Part of understanding the history is researching what you have and determining it's authenticity. I only want peer reviewed FACTS. There are too many people who fall prey to con artists and purchase crap thinking they just acquired a piece of history....a little too trusting of society....I am happy I found this forum, and have been thrilled with the level of expertise with which fellow numismatic fanatics respond. If it ain't real....I want to know....and that makes collecting the AUTHENTIC stuff that much more fulfilling!!!
For scarcer bronzes especially I try to find die matches to verify the coin hasn't been tooled. Not always easy but it helps that there are millions of coins pictured online. Luckily so far the only "surprise" I've found was finding proof that a particular coin was the scarce bronze I suspected it was and not what the auction house misidentified it as(via a die match found in a Spanish eBay seller's inventory).
Certainly not I. The question we all must face is just how much we let this uncertainty drive our hobby. We have shown examples of fakes that crept into the most respected major auctions so only dealing with the big boys is not 100% certain. Many of us are 99% certain of the status of 90% of the coins we see so we can just avoid the 10% in question and have only a few fakes. I try not to let it ruin my enjoyment of the hobby. If you want certainty in anything, just remember the old saying about death and taxes. I do suggest you pay your taxes.