[MrB]

what caused Zimmerman such consternation upon seeing a person walking through his neighborhood?

I believe it was the incredible number of burglaries in his neighborhood in recent months. When is "enough"?

[SoothingDave]

Hence, the neighborhood watch.

Note, the word is “watch,” not “accost.”

[Clara Lou]

But what kept Zimmerman from simply watching the boy from a distance until he reached his destination? Why get out and confront? Zimmerman made mistakes that precipitated the incident.