
Please read the disclaimer
Quick Recap: The Four Noble Truths discusses how 1) Existence is suffering; 2) Suffering has a cause; 3) Suffering can cease; 4) Suffering ceases by following the Noble Eightfold Path.
The thing I like most about the Noble Eightfold Path is that we knew all of this stuff when we were two. If you know any two year olds, you know that they have a very well defined sense of good and bad. With my own kids, all I would have to do is say, "That's a bad word!" and I could see how upset they were that they'd done something "bad".
But somehow, we lose sight of that as we get older. My personal take is that as we age, we learn of "exceptions" to the rules, and soon we begin to take advantage of these exceptions for our own personal benefit. For instance, we tell ourselves that "white lies" are ok, as they spare other people's feelings, and then we start stretching the definition of a white lie when it suits us.
The Noble Eightfold Path is profound, and like most profound things, very simple.


Right understanding - The Buddha is said to have remarked that, "I must state clearly that my teaching is a method to experience reality and not reality itself, just as a finger pointing at the moon is not the moon itself. A thinking person makes use of the finger to see the moon. A person who only looks at the finger and mistakes it for the moon will never see the real moon." You have to use the tools (the Dharma), and you have to make sure you understand things correctly (through getting help from the Sangha, or Buddhist religious community).
Right intent - Why you're following the Noble Eightfold Path is as important as the path itself. You should be following the path to further your belief in kindness and the equality of all life. Follow it for other reasons (to impress your friends, for example), and it will not work.
Right speech - Speak kindly and truthfully, with an eye towards the happiness of others.
Right action - Do the right thing. (Pro tip: You know what the right thing is. It's usually that thing you make up excuses for not doing.) Right action takes into account the Five Precepts (not to kill, not to steal, not to lie, avoid sexual misconduct, and avoid drugs or intoxicants of heedlessness).
Right livelihood - Don't work in an industry or area that requires you to compromise your beliefs or that causes harm to others (e.g. arms dealer)
Right effort - You have to try. You likely know people who will go to church on Easter and Christmas Eve and feel that is spiritually sufficient. You want the opposite of that. You should prize clear, honest thinking, while leaving behind negative, destructive emotions.
Right mindfulness - Mindfulness is the absorption in the present that helps you protect yourself from harmful thoughts. For instance, if you revel in thoughts of revenge, you will suffer. But if you are mindful, you will catch these types of malicious thoughts before they take hold.
Right concentration - Once our minds are free from clutter, neuroses, and conflicting emotions, you must then use right concentration to focus the mind (on a subject of concentration while meditating, for example).

I find it interesting that there is nothing in the Eightfold Path that is fundamentally Buddhist in nature. You're not required to believe in the Buddha (not even as a Buddhist, in fact), you're not required to go to a Buddhist temple, you don't have to meditate (although it definitely helps), etc.
And that, I think, is why you find that genuinely nice people tend to be happy: They're pretty much walking the path already.

Disclaimer
There are a few things to keep in mind when reading this post:
- My knowledge of Buddhism (or anything else, for that matter) is most definitely not total or complete.
- There are different schools of Buddhism and at times they disagree with each other.
- More than anything else, this post is a tool for me to better understand Buddhist concepts through writing, as writing about a subject causes the mind to approach it in different ways.
- If you are interested in the subject, please do not assume that what you have read here is correct. Read, think, and decide for yourself!

Page statistics of no interest to anyone, including myself
- Favorite word to type: Heedlessness
- Best sentence: "You know what the right thing is."
- Number of steps I usually remember off the top of my head: 6
- People I know that fully walk the "anti-path": 1