Jesus said: "For if you love those who love you, what reward have you? Do not even the tax collectors do the same? And if you greet your brothers only, what do you do more that others? Do not even the tax collectors do so?"
Usually, I have no problem being nice or gracious to those I don't know. It was something instilled into me from a young age and further reinforced by my faith. I've always thought that I had this passage down pat.
I'm finding my problem is that it is easier to be kind to stranger than to those close to you. I'm not sure if it is because I know them better (and so know their faults) or if it is that I'm known better by them (and they know my faults). Whatever the reason, I find myself much more harsh towards those closest to me, whether it is my wife, my friends, or my employees. There is so much less to lose by being gracious and loving towards strangers, but so much vulnerability to be humble and caring towards your closest companions.
I should, at the very least, be treating those closest to me as tax collectors.