You can keep it.
I say 'howdy' to everyone I meet... Or at least a nod and a hat-tip... It is not uncommon to pass the time of day with a total stranger, met on a park bench or lunch counter, or some such.
How folks live otherwise is nearly foreign to me. And I like that.
"Hello" or Howdy is how it starts. The whole point is to stop you and break your momentum. If you keep walking without answering or looking at them, then you are just a ghost that flew by. However, if you answer them or god forbid stop to talk to them, you have just become human. That lets them know that you are a mark.
Then they will ask you something innocent like directions or where is the bus stop. But, in every case, after they ask for a cigarette, somehow the conversion will veer into, 'Scue me sur, do you have any change you can spare? I'm trying to get home to see my sick mama.' Happens every time.
Nobody in the city needs 'directions' or to know what time it is. They will say anything just to stop you and to direct your attention to them. Once you do that, they know they got you. The best way to respond is to say nothing, do nothing, don't look at them, and most of all do not ever slow down or stop walking. This will not deter the more aggressive ones, which is why I carry a knife.