My regret was buying this falsely advertised raw ASM 700 book a little while back! I was just getting back into comics at the time and this dude was offloading his collecting, which most were junk, but he said he had this one kept away and pulled it out for me saying it is the rare Ditko book. I thought the cover was cool and giving the guy the benefit of the doubt, I paid $200 and took it straight to LCS for grading. LCS looked it over, did a quick check on the internet, and confirmed it was the book. A month goes by and I got my submission back with the NG label and note saying coverless copy - felt like such and insufficiently_thoughtful_person and the guy at the LCS was shocked too. Needless to say, I became much more thorough from that point forward...
I still keep the book around as a reminder to myself of how my "come back" began -- good times!