I have in the past been inspired by others who have taken up a cause to help and I have joined in but somehow haven't the confidence to weigh in all on my own - I think I'm best at giving kids money for bus fare they have lost etc. When its bullying I don't really have a clue what to do

Depends on the injustice I suppose. I prefer to assume others have the same capabilities as myself, and I know I would rarely desire someone else stepping in to defend me, and I treat the world accordingly. However, I will happily offer assistance to anyone that asks, if I am reasonably able.

If someone needs help, but is incapable of asking due to circumstances, then yes, it is wrong to look the other way.

I'd say it's upon us as a society to intercede where we can.... Buuuut that's when we get bombing runs on Syria, inept skullfuckery in Iraq and the ramping up of tensions with other world powers.

On a personal level, I have always been proactive about stepping in to help strangers — but that changed a little since I had a child; I'm much more cautious about breaking up violence in the street as I now have a responsibility not to get myself stabbed — and I wonder if that should ramp up to how nations conduct themselves too, if you get my meaning?

A kind-of related thing: I'm a bus driver, and I sometimes land myself in trouble as I will carry homeless people and street-drinkers for free if they need to get somewhere. I feel that if a person has slipped through the cracks then society has a moral duty to help them.

There is some of that but, on the other hand...there is some of mind your own business, you know?

In principle, it's never right not to stand up to injustice but as the phrasing of your question suggests it is YOUR perception and it is easier than most people think to be wrong in judging a situation. For example the other day two young boys, probably about 10 and 7, were walking past my house. I wasn't particularly paying attention to them but then I became aware that the older was hectoring the younger with words to the effect, "the sooner you get it through your head that you're a fucking idiot the better". That sounds like bullying. But ... for all I know this was an older brother giving some tough love to a younger brother about a specific situation, or it was just empty bluster. Even if it was a truly abusive situation -- as another poster mentioned, they might have both turned on me or flipped me off; people are funny that way. Anyway it was over before I had time to process it and they were on their way.

Was that a moral failing on my part? I still don't know. I must also confess that at my age I no longer feel responsible to Save The World. Mostly, it doesn't want to be saved anyway.

It is always wrong to ignore or "look the other way" in a situation where your words or actions could assist someone suffering injustice, or prevent it altogether.

I've wondered about this regarding police officers doing something I think is an injustice or a crime.

We've all probably seen videos of, or experienced in-person, a group of people stopping injustices (tackling a robber at a convenient store, defending someone being verbally harassed or physically threatened in public), but what if the person responsible for the injustice is a police officer?

What would I do? What should we do?

Do I/we try to stop the officer and potentially run the risk of being beaten, maced, arrested, and/or having jail time? Police officers are trained to trust and protect their own (other officers) in times of crises, so if you step in to confront a police officer responsible for an injustice (whatever that may be), when back-up arrives, they are not going to be taking your side and helping you.

Yes.

once upon a time we took a family trip to Mackinac island. One day this scene that could have been straight out of a "What would you do? 20/20 episode" unfolded before my daughter & I whilst my husband was walking ahead of us.
This woman, about 1/2 a football field away from us was yelling at this young girl, (who didn't look like she could be older than 10) when all of a sudden this woman slapped her hard in the face. I LOST IT and reacted to my horror by yelling at her. There were TONS of people around! Surely my girl and I weren't the only ones who saw this? As the slap was prefaced by screaming at this poor girl. The boy that was with them flipped me off. I SO wanted to call the police but they disappeared before I could alert my husband, who was wondering what all the commotion was about and got angry at me for yelling (he missed the entire thing).

Well THAT erupted into an argument between US!

Him "Just mind your own business!"
Me: Seriously???? You're OK WITH THAT??? The rest of that trip was interesting, needless to say. My biggest memory of Mackinac island trip, being "splained" by my husband & witnessing a despicable parent slap the living --- out of her kid.
I was crestfallen that no one else said a peep and that he didn't have my back on it.

It shocked me as we were never corporal punishment people, that he could ever be ok with a kid being abused like that much less in public. It left me and my girl totally disgusted.

You know what? I think it's an injustice that sports players make millions to play a game while someone who works 80 hours a week in a factory might still get a poverty wage. But my opinion is just an opinion. So I don't watch sports and I'm a union steward/agitator, and I vote aggressively pro labor.

What's an injustice? Anti-abortion people go to the extreme of property damage and murder because of the "injustice" to some embryos. What are you entitled to do to prevent injustice?

All it takes for evil to flourish is for good people to do nothing.

That is a complex question. Getting involved in other people's domestic disputes can be fatal. It is one of the leading causes of police deaths, and they are professionals in handling disputes.

Depends on how serious or trivial the incident is. IMHO