Slightly Heraclitis in that change is inevitable so effect what change you can and accept what you can't. The route to a happy life. The latter is a lot more challenging than the former as we all know!

We can't be responsible for what happens to us or how other people act. We do, however, have a choice in how we respond.

How much?? ...how about everything... Everyone is responsible for their own actions to move forward towards whatever, make them happy, wealthy, healthy, productive, athletic, lazy, useless....any possible scenario is fair if that's what one wants to be. The only thing not fair at least in my book is to blame my own shortcomings on someone else.

I believe there is always something you can do to affect change in your own life.

Well it really boils down to what kind of situation you have yourself in. If you're living with some kind of disability and that slows you down in life, the action or inaction is less consequential. Seeing as that doesn't apply to every given case, you need to take responsibility for everything that's in your power to control. Life hits everyone in different ways, and we all get dealt our cards. How you play them is what really matters though. Even if you have a bad hand metaphorically, you can always try your hardest to make the best play as possible, and you always should at least attempt it. The cause and effect of owning up to your choices to do or not do something is an everyday necessity. Only you can decide whether or not your actions are steering your moral compass in the right direction.

I find the question a little confusing because it's posed initially as a person being responsible for himself or herself, and then shifts to how responsible we are for things that occur around us.

I'll answer both.

100% responsibility for oneself.

To the best of his or her ability, 100% responsibility for an occurrence or event that one wishes to improve, help or reverse. In other words, wishful thinking while complaining about it is not enough.

0% responsibility for the action of others, in the case where the other is not a minor or dependent.

You can't control everything, and you have less control over yourself than people want to admit. If you don't believe me check statistics on dieting.

You are however responsible for everything you do. Do not confuse control and results for responsibility. To use an extreme example everyone will understand, it is your responsibility to protect your children but that does not mean you can control what happens to them. Regardless of your ability to completely control the outcome, it is still your job as a parent to live up to your responsibility.

None. Blame the immigrants for everything! If they weren’t here, nothing would go wrong in any of our lives. So it’s all their fault—always.

Always take responsibility for your actions-its part of being an adult.