[m0nty]

> If I helped someone the only thing I'd expect in return would be that if the person I helped is ever in a situation where they can provide help to someone else, they'll remember the time they were helped by a stranger and take action.

You say that as if it's a minor thing ("the only thing I'd expect") but you might be expecting someone to risk their life, get accused of rape by an unstable person, put themselves in danger of injury or lawsuit. It's not a trivial matter. I personally wasn't expecting anything from this person I helped, I was just pointing out that she ended up being no different from the other drivers around her - just less fortunate.

As Anderkent says, on a basic level, we're all expecting "something in return". We help other people, maybe they'll help us one day. But this instinct is tuned to small communities (in which we evolved) where "paying it forward" like this is very likely to occur in a short space of time. You help me carry my kill home, you can have some of the meat. You help me get my harvest in, I'll help you raise that barn. But in large communities (several million strong, in some cases) these opportunities will be limited so we are more reluctant to get involved. We might not be consciously weighing profit and loss, but on a subconscious or instinctive level, we are.

[wozniacki]

  You say that as if it's a minor thing ("the only thing 
  I'd expect") but you might be expecting someone to risk
  their life, get accused of rape by an unstable person,
  put themselves in danger of injury or lawsuit. It's 
  not a trivial matter.

Strongly seconded.

This happens more often than one would think.

I do not want to alarm anyone but it is not entirely out of the bounds of reason to expect law enforcement to NOT acknowledge your good Samaritanism or worse, punish you for it.

"Good Samaritan Backfire or How I Ended Up in Solitary After Calling 911 for Help"

Discussed previously here on HN :

How I Ended Up In Solitary After Calling 911 For Help

https://news.ycombinator.com/item?id=7233730

Direct link to blog :

https://medium.com/human-parts/9f53ef6a1c10

[hollerith]

That guy did not leave after the police arrived and told him to leave (according to his own account, at the URL you give).

[metastew]

But does that even justify the police brutality though? He didn't want to leave without his friend (who was supporting the girl while she was getting up when the police pulled him off).

No, the police is definitely in the wrong here.

[netcan]

That sounds not very far removed from: "She burned the dinner after I told her I was hungry.

[hollerith]

>You help me carry my kill home, you can have some of the meat. You help me get my harvest in, I'll help you raise that barn.

What you describe is reciprocity, trading favors or "paying it back". "Paying it forward" is something different and rarer.