It's one of those unwritten rules in wrestling. If you headbutt a wrestler of Samoan origin it's not going to hurt them but it will probably hurt you. The Headshrinkers tag team of Samu & Fatu (Rikishi) were known for doing it although it probably started before they were doing it. When somebody gave them a headbutt they didn't go down. The person delivering the move would end up falling on his back or get stunned after delivering the move. You don't see that happen in wrestling. That tradition of headbutting a Samoan with no reaction has been used by others along the way like Haku/Meng, Rikishi (when he was in singles), Jimmy Snuka and others. Even some current WWE stars like The Usos, Roman Reigns and Tamina Snuka have also had those moments where they don't sell it. It's a funny spot to see somebody oversell when they're doing an offensive move like a headbutt.
John wrote at WhatCulture from December 2013 to December 2015. It was fun, but it's over for now. Follow him on Twitter @johnreport. You can also send an email to mrjohncanton@gmail.com with any questions or comments as well.