How about instead of just telling everyone they are wrong in this thread, give detailed explanation on: 1. Why they are wrong, and 2. What the best explanation is.
To some extent, the will to get up and fight when they're hurt and tired. But sometimes their bodies just can't recover quick enough, no matter how much they want to go on.
Look at David Price. Zero chin, but tons of heart and guts. This guy is always going out on his shield.
They're wrong because ones heart has zero relationship with one's chin.. Having to explain the obvious is crazy..