Motivation?

with the kyle maynard fight in the headlines it got me thinking and I was wondering how motivated people generally are in training? i come from a wrestling backround and was thinking about how i needed to be pushed and remembering how occasionally i'd almost welcome an injury. when i look back at my wrestling its like the best time i'd never want to do again, if that makes any sense.

is it like that for fighters/other combat sports as well? Are the ones who make it pro the ones who push themselves? or is it a little bit of both like it is at all levels?