Simple principles that you may or may not know but that will affect how you relate to others in a significant manner. You could sum it up with saying, it's not that we do unto others what we'd have them do unto us, but that we should do unto them what they want.
The way by which you feel loved is usually the way you express love to others, but this is not necessarily the means by which they feel loved. Express your love for others in your life using the channel, or language, most effective for them.
I couldn't finish this book. It seemed like a waste of my time. First of all, yeah, I see the "five love languages" but I don't think anyone needs just one. I think these are five descriptions of ways people show love and people are more complex than he thinks. I don't have just one "love language" (sorry, Mike).