Treat others as you wish to be treated. Don't just be nice, but be kind to other people. That can be so rewarding.
When we borrow trouble, and look forward into the future and see what storms are coming, and distress ourselves before they come, as to how we shall avert them if they ever do come, we lose our proper trustfulness in God. When we torment ourselves with imaginary dangers, or trials, or reverses, we have already parted with that perfect love which casteth out fear.