Based on a real life incident where I was put up against someone who towered over me. As usually the highest ranked guy on the mat besides the instructor I am usually put against extremely new people.

You sometimes get 'thugs who watch the ufc' come to the club and learn skills...However they got a chip on their shoulder and come into it saying "I am not gonna tap". I am extremely friendly and a very slender man in real life, so I am very unassuming and some people tend to think I am not a fighter, just a nerd and the academy is just like a karate dojo (aka a Mcdojo filled with people who can't fight out of a cardboard box).

So when we are paired off, we stand in front of who we are paired with and the guy was much more athletic then me, he gave me a look over then smirked a very cocky smirk. My instructor told him "You get Michael, he will help you, and he takes care of new guys".

As we drilled he was ok to drill with but when we finally sparred, we started with back mount with hooks in (basically riding the guy like a back pack) and he flailed and exploded to get out, but he was no way near getting out all while I was going for a rear naked choke to prove I can choke him without the collar, so he attempted to defend his neck as you would defend a head kick in thai boxing. Which is putting your hand behind your head and have your elbow cover the temple....But he went so fast and explosive he punched me in the eye and attempted to stand up after he noticed he hit me.

Now.....Lets be clear....I am a nice guy. I don't go out there to hurt people, if I got a limb lock, I try and just hold it then start to slowly hyper extend so they have a good chance to tap....But when I get hit, something inside me clicks and it is go time...I just go explosive and almost see the red mist in a way. So instead of stopping him, I DOVE for an armbar and YAAAANKED, and because he tried to stand up, gravity made it even worse.

His arm clicked 4 times before he verbally yelled tap, he said it did not hurt though, then as we cooled down he said "Oh....Shit....My arm hurts man" and I never saw him again, I guess he could not take a small guy beating him, because I know the arm did not get mangled and he took a while to tap due to ego.

Moral of the story is, size helps only when you have the same skill level as your opponent, if you rely on strength and a warriors mindset, you will get hurt and humbled very quickly.

Thank you  vogelrove For the arts as well as a good bear character to armbar