The “greedy robber” makes me suspect that he had been smoking crack and though still out of it desperately wanted to smoke more. But the crack house said, “No money, no crack!”
This happens a lot. They immediately go into a “Must get more money NOW!” mode, and nothing else matters.
Someone first noticed it when they left their apartment building, and heard somebody scream at a distance. It took him a while to realize that they were trying to rob him from about a block away, holding a knife and demanding money, but shaking so hard his intended victim could tell he could barely walk, less run.
“Come here and give me money!”
Out here it’s more likely meth and heroin.