So many people have told me throughout my life that I need to just ignore it, and you can't save the world. I can't help but think that's just their way of trying to invalidate any guilt of their own, even if they're right that it's not possible to help everyone everywhere.
Though that's why I invest on Kiva, because I can help make an impact in a "starving" part of the world helping to build up economies so the people can take care of themselves, rather than solely relying on financial donations.
Feeling guilty isn't solving the problem, however. Guilt is just a pre-cursor to either resolve or apathy. If you don't do anything about it, you either get into a loop of guilt-> apathy-> guilt or you choose to ignore the problem (as you say your friends do).
Any action you take towards true progress for those in need, no matter how small, is good.
"The journey of 1,000 miles begins with a single step"
My original intention for discussing my guilt was that I know it's a common feeling, and I wonder why so many people take action/interest for high profile cases. It's likely the overwhelming sense of apathy towards "saving the world" that people zoom in on particular people that they're familiar with.
But I still can't help feeling guilty for trying to help someone I know, versus a very needy person I don't. I'm not sure I'll ever be able to not feel this way. Ignoring the emotion only seems to bury it, only for it to resurface in the future (similar to your guilt->apathy->guilt cycle). One thing is sure though, even after I help someone, I still feel the sense of guilt and frustration that pairs knowing the rest of the world is still in need.
Like you said, any progress, no matter how small, is good!
Though that's why I invest on Kiva, ...
Do you feel like you're not making enough of a difference? You're already helping more people than most people out there.
So no, you don't have any ethical obligation what so ever toward somebody else. Even if eating out of your garbage could save their life you would be well within your rights to decline.
But really once you stop feeling like it is your responsibility to do something for anybody, no matter how great their need or how trivial it is for you, you feel so much better -- and you can still help somebody if you want to. You just have no obligation.