For those who carry firearms, do you feel any obligation to use them if there is a need?

Inspired by @josie’s question – Assuming your state allows it, do you have a Concealed Carry Permit. If so why? If not why not?

If you have a weapon with you and you’re caught in a situation where someone may be hurt, do you feel obligated to intervene because you may be the best prepared to?

If you’ve thought it through beforehand, what situations would you intervene and which have you decided wouldn’t be worth getting involved?

If you’ve ever needed to make that decision, and are willing to share, how did that go?