Some where along the line, the observe part got tossed out
That's a mighty big assumption. Zimmerman may well have been observing right up till the time Martin started beating. The autopsy report made no mention of any damage to Martin, other than the gun shot wound (unless the injuries to his knuckles were from Zimmerman beating Martin's fists with his face). As I noted previously, it is highly doubtful that Zimmerman shot Martin prior to Martin laying the smack down on him.
This could be the case... where the kid doesn't take kindly to being followed, turns around and starts mouthing off and from there egos start flaring and feathers ruffle while ol' Z just sheepishly turns and retreats having done (or said ) absolutely nothing to agravate an already potentially volatile situation, then TM decides "hell, I'll just whoop his a** any way".
This is the is the scenario that I'm perceiving is being suggested.
I'm not suggesting that Z assaulted TM in any way prior to the shooting. 
From a legal stand point (if this is more or less the way it went down), not taking into account what words
MAY or MAY NOT have been exchanged before the actual physical altercation, Z
is justified in defending himself while he was getting thumped.
But no one seems to be asking what it was that triggered the whoopin.
In my experience, roughly 9 out of ten physical altercations on the street could have been avoided if at least one party would have just grown up, put away their ego and defused the situation with a some verbal conflict resolution skills (definitely not in high abundance with people in general, unfortunately).
And afterwards, everyone plays the "saint" saying "I didn't say anything to him, I don't know why he wanted to kick my a**"
....yeah, sure buddy . I can say this because at a younger age, I was one of those knuckle heads who while in the Navy was always getting into bar fights even up to about Zimmermans age.
Having taken quite a few painful and unnecessary bumps and dings, maturing, and looking back, I know that almost everyone of those situations was totally avoidable (except in the case of the Australian sailors who see brawling with other sailors as a way of showing affection, followed by a couple rounds of beer
).
Yes, I know, from a legal stand point it doesn't matter (it was happening and Z defended himself justifiably). And the idea that "it could have been avoided" seems to be irrelevent, in the opinions of many here.
OK I guess, from a legal standpoint but a human being is still dead when it quite possibly didn't have to go down the way it did. And I won't presume to play "God " and judge the amount of worth on anyones life in this case.
And although the thumpin that TM gave him may not have been justified (if Z is telling the truth about so innocently retreating without so much as a word), I just don't buy the whole "I'm just a dedicated model citizen looking out for my community while minding ALL my Ps and Qs" thing.
I know it doesn't mean squat in court, but I think the kid (right or wrong; probably wrong though), thinking "I'm not doing anything wrong, WHO is this guy", turned and told Z to hit the road, Z got cocky and talked some trash because he knew he was packing.
The kid then probably decided he wasn't going to take Z's "Barney Feif" BS and went up and put Z on his shelf.
Street mentality Vs. Barney Feif.
If this is more or less the case, like I said Z is legaly justified... but in my opinion, still the bigger jackass of the two.
"...mans got to know his limitations"
