Quotes from the Screwtape Letters have not been terribly well-received in this thread. So, perversely, I decided I had to take a turn:

Do what you will, there is going to be some benevolence, as well as some malice, in your patient's soul. The great thing is to direct the malice to his immediate neighbours whom he meets every day and to thrust his benevolence out to the remote circumference, to people he does not know. The malice thus becomes wholly real and the benevolence largely imaginary. There is no good at all in inflaming his hatred of Germans if, at the same time, a pernicious habit of charity is growing up between him and his mother, his employer, and the man he meets in the train. Think of your man as a series of concentric circles, his will being the innermost, his intellect coming next, and finally his fantasy...you must keep on shoving all the virtues outward till they are finally located in the circle of fantasy, and all the desirable qualities inward into the Will. It is only in so far as they reach the will and are there embodied in habits that the virtues are really fatal to us.

-- The demon Screwtape, on how best to tempt a human being to destruction.

The existence of souls notwithstanding, Screwtape is clearly right: if you are charitable to almost everybody--except for those your see every day!--then you are not practicing the virtue of charity and are ill-served to imagine otherwise. You cannot fantasize good mental habits into being; they must be acted upon.