For all the talk about Napoleon complex, a reverse Napoleon complex also exists in my opinion: many people who consider themselves as big absolutely hate losing to people who they consider small.
I'm 174cm (roughly 5'8 and a half) and growing up as a kid was always on the shorter side. I grew up on a farm and wrestled some and also did some basic gymnastics as a kid, so I was a short and relatively skinny kid who could ragdoll kids 'three times the size of me' using Conor's vocabulary.
Whenever play fighting with one of those types escalated into a full-force grappling scenario, the tall and skinny kids who considered themselves as 'big' and to be untouchable to the likes of little old me were the ones who found themselves stuck in a neck cranky headlock the longest, too proud to be humiliated by someone that much smaller than 'em or something. Quite often they would also re-engage immediately after I let go, probably biting down on their teeth and fully believing that it was just a fluke and wanting to show that to everybody else watching, this time by going all-out.
Never did the outcome change.
These type of kids were also the kind that would often wind up extremely butthurt from being beaten and be incapable of letting it go for days, or some for even weeks afterwards.