A matter of geography or virtue?

I love this quote from Fulton J. Sheen:

"There are many who excuse themselves, saying that if they were in other circumstances they would be much more patient. This is a grave mistake, for it assumes that virtue is a matter of geography, and not of moral effort. It makes little difference where we are; it all depends on what we are thinking about."

I often talk about the same thing in my books and my talks. We may think that the reason why we cannot act in a more virtuous manner is because we are enduring an insurmountable circumstance, suffering, or situation. "Of course" we tell ourselves that if we were in another situation, related to someone else, had a more virtuous spouse, or a more kindly boss, we would certainly act differently. Who are we fooling?