
A recent tragedy is a perfect example of complacency, of arrogance in self-defence , i.e.what not to do.
http://www.ferfal.blogspot.co.uk/2015/05/argentinas-strongest-man-stabbed-to.html  [ a good urban/economic collapse survivalist site BTW ] 
"Alan Garay (43 years old) was a 260 pound “strongman” that won 
competitions both in Argentina and Spain. He could lift 880 pounds, pull
 15 ton trucks and lift cars with little problem, but that didn’t save 
him from getting killed two days ago in the province of Mendoza, 
Argentina.
After an argument with Fernando Pezetti, a 50 year old 
cartonero (paper and trash scavenger) over trash left on the sidewalk 
next to his house,  Mr. Garay got into a fight with the man, easily 
overpowering him and punching him in the face. As Garay left, the 
scavenger produced a knife and stabbed him twice in the torso. The 
neighbors called for help but Garay was dead by the time help arrived.
Garay
 had lived in Madrid for ten years and had recenlty moved back to 
Argentina. He worked security at night clubs and at times was part of 
security details of international celebrities.
Lessons Learned:
1)Don’t get into a fight if you can avoid it.
2)Don’t
 EVER underestimate your opponent, even if you’re literally the 
strongest man in the country going against some random 50 year old hobo.
3)Always assume your opponent may be armed, NEVER turn your back on him.
4)Knives
 are ALWAYS lethal weapons. They don’t jam, they don’t run out of ammo 
and its practically impossible to pry one away from an attacker without 
losing a few fingers.
5)Again, just don’t get into fights, ESPECIALLY against someone that has nothing to lose.
FerFAL"