Most people, you've noticed, just aren't pleasant. You look kindly at them as you pass, and all they do is return a nasty scowl. Your first instinct is to chase them down and demand a smile. But, you know that won't happen. Take kindness upon yourself. Say hello to everyone: who cares if they don't respond or think you're crazy? You're doing this for yourself, not for their benefit. It good for your soul.