Over the course of our lives, we meet all types of people -- smart, courteous, obnoxious, rude, and everything in between. While we all wish we could meet only people who make a positive impact in our lives, each and every individual serves a valuable purpose. In fact, those we come across generally fall under one of two categories: 1. They're a blessing. They lift us up when we're feeling down through their infectious optimism, generosity, and sense of humor. They exhibit warmth, kindness, and hospitality whenever we're around them. Time seems to fly when we're conversing with these wonderful souls. Even if we go weeks or months without getting in touch, we can easily pick up where we left off. They're not all smiles all the time, though. When we're out of line, they're not afraid to put us in our place -- yet, we don't mind because they do so tactfully. They're a welcome enhancement amid a sea of fakers. 2. They're a lesson. Let...