On NintendoAge you learn that everyone has opinions and you get about a dozen passes or so...even chronic antagonistic behavior is accepted as long as it's localized.
We like to butt heads a lot here on the site, but in a sibling kind of way.
It's best to move on and maybe even try to reason with the guy if you feel he did you wrong...also there's an "earn your stripes" attitude to this community too.
I wouldn't pay too much attention to one negative comment, because if you're really looking for top tier items at a better price than Heritage Auctions then this is the only forum to be really.
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Got any of these for sale? Sell them to me. I also buy other NES Publisher inserts, and even GB/GBC, and SNES inserts too.