I wanted to publish a post about "jobs" already some time ago but I didn't have the right picture. Now I have, here is the post...
To be honest, I don't really know how you call somebody who polishes your shoes in English. The Spanish word is
botanero and you can see one of them on the pic. They are quite common here and some time ago it was a notable job.

For me as a German it is still quite strange imagine having somebody polish your shoes. I would feel a bit bad because I don't want somebody "getting to his knees" in front of me.
But to be honest this is not the only service you get here and which seems a bit strange to me. There are people who wash your car. For 30
pesos (a bit more than 2 €) and many people tell them afterwards where they have to wash or polish again because their car doesn't shine enough.
Then, there are people on the carpark of the super market, for example, who "help" you getting into and out of your parking spot by blowing a whistle and making wild gestures. After your shopping they expect a little tip. And they are not there because Mexicans can't park (although...). Usually those people don't have a proper job and try to earn at least a little money by that. You should know something like a social system doesn't exist here although there are a few ways you get help from the state.
Something else which doesn't exist in Germany (and I guess the rest of Europe) any more: filling station attendants. Of course they expect a little tip, too.
There are people who don't do anything else but waving a red flag at the railroad crossing. To tell you, you can pass...
And the best (I saw it when I came to the internet café): People painting
topes (humps to reduce your speed). Of course expecting a little tip for it when you pass.