Especially If They Are Mixed Martial Artists
*shout out to ModernMan.com!
Why? The answer begins at the root of mixed martial arts, long ago, when the Brazilians inherited and developed the ancient...you know, let's skip the history lesson. It's because of dudes like Mauricio "Shogun" Rua.

You know who Rua's best bud is? The guy who you would ostensibly be the
one to pull Rua off of you while he stomped your skull as casually as
most of us make a pot of coffee? Shogun hangs with a gentleman who goes
by the moniker of "The Axe Murder". Meet Wanderlei
Silva.
You don't get that nickname for selling more popcorn than the rest of
the boy scouts in your troop; you get it for causing bloody violence to
occur, for fighting as if you are the only natural predator in the
jungle. Like Blanka from Street
Fighter II (another legendary Brazilian beast), this guy will
choke, kick, knee, punch and possibly claw you without mercy (at least
he can't give you electric shocks) until you are no longer
recognizable to loved ones. After the bloodletting, though, he might
help you up and give you a few pointers. People say he's a heck of a
nice guy. He looks it.So what, right? You could spotlight a couple of superhuman aggro pain-administering borderline psychotic scalpers from any number of countries, right? No matter where you go, you're bound to find at least a couple of guys, often fighters (or inmates), who don't have that hesitation-toward-violence switch that normal people have. Okay. Let's find a couple more examples of why you should never ever ever ever engage in a melee with a Brazilian under any circumstances. These next two guys perhaps aren't as aggressive as Shogun Rua or The Axe Murder Silva. No, these next two aren't like that. They're like this: the best fighters in the world.

Rua, Wandy Silva, Aldo...who is left? How many badass Brazilians are
out there?
How about the best fighter on planet Earth? His name
is Anderson
"The Spider" Silva, and the good thing about any hypothetical
fisticuffs an Average Joe like yourself might find yourself engaged with
Silva, the UFC Middleweight Champ, is how small the chances are that
you would even know what had happened to you. The blows would come too
fast for your nerves to properly acknowledge them, and you'd be out on
the side of the road attempting to unscramble your brain, body and bow
tie before your cognition skills were able to process anything more than
the fact you survived. Mostly survived.
We're clear on this, right? Never, ever EVER EVER? And which dangerous
Brazilian fighters did I leave out? Who are your favorites?