I truly believe putting good thoughts out into the universe brings good things back to you. A friend puts it more simply - Good energy brings good things. That being said, I hate it when someone says, "there's good in every situation, it's up to you to find the positive in the situation."
I would love to say to them, "Really, what's the positive of the sudden death of my family member who was only 8 years old? She wasn't ill, wasn't suffering so explain the positive in that situation." I'd be interested in hearing the response to that question.
I really wish people who think they're being well meaning would think before they speak. You may not be aware of what someone around you has gone through or is going through.