The next time you're upset with someone -- at home or at work -- pretend that you need to write a letter of recommendation for that person. It doesn't have to be real long, but at least three short paragraphs. It does have to be sincere.
Composing the letter reminds you of the person's good traits. It's a matter of creative focus: Look for what's wrong, and you'll find it. Look for the good, and it's there too.