Fighting game bosses are typically meant to be understood as the most difficult enemy of any fighter. Traditionally they were unselectable characters and the very last or second to last opponent in the game before you get to the ending sequence, or in the case of 3D fighter coin-ops, just the game credits. The experience of bringing the arcade fighter home significantly lowered the frustration of losing to an incredibly unfair boss fight, it doesn't change that most bosses were designed to be intimidating and and just downright cheap. Now to the very well seasoned veteran of any fighting game defeating the final boss is a matter of understanding the game mechanics and AI behavior, but any casual player with no previous knowledge of a fighting game's strategy will be mercilessly manhandled.