Never headbutt a Samoan

Hi Scott

I was watching a video about the old Joe v Angle feud in TNA, and something jumped out at me. Angle headbutted Joe, and came off best.

So:

1) Is the "never headbutt a Samoan" thing a WWF/WWE exclusive in-joke?

2) If not, is Joe somehow considered different from the other Samoan wrestlers in some manner?

3) If the theme does still apply universally, is Angle then the only man who has come off best when headbutting a Samoan?

I feel this is a vital question I need an answer to prior to Joe hopefully shocking the shit out of everyone by beating Lesnar to a pulp and getting the title back to weekly TV exposure.

​Yeah, but we already established that Joe is the only Samoan somehow not related to the Afa/Sika family tree, so clearly he doesn’t have the same superpowers. QED.​