and never treat someone worse than you would want to be treated.
If I can take a different turn on this from Hawkeye - this is both right, and a load of rubbish.
The reason it is right, is because we should always have empathy & respect for others when dealing with them.
The reason it is a load of rubbish is because you have spent your life being a nice guy...which leads to problems when things get difficult.
When people treat deliberately hurt your feelings, you don't treat them with sweetness, nor do you roll over and accept it.
When people deliberately hurt you - it's fine, and right, to get angry (deliberately hurting you can come in many forms : manipulation, stabbing in the back, sleeping around behind your back, crap gossip etc).
...of course, there is getting angry, and there is getting vengeful/petty etc (which are two different things. One shows the persons emotions, the other shows the persons character)
One of the things that I've been trying to show you is that you need to build the foundation that is you. Currently you are seeking approval from everyone else as to what your worth is. That's like building a high set stone house on skinny wooden stilts - the house looks great, but if someone kicks a stilt, it all collapses, and you wonder what's wrong with the upper storey...rather than realising that you need a more solid foundation. And so you build it up again, and the stilts get kicked out...and you blame the masonry. And you build it up, and the stilt gets kicked out again...and you think it's impossible to build a house - that you can never have a house that stands...
The skinny stilts are your individual self, the stone upper floor is your social self. If the bottom floor were also made of masonry, it wouldn't matter how much someone kicked - the upper floor would still remain standing, and you wouldn't believe that it's impossible to build a house that can remain standing up...Ie. you'd feel much better about yourself.
That is to say, start doing things for you, because you like them, and because it is you, and because you value what it brings to your life, and you value those qualities in yourself...and the social side of you can be constructed on top that.
The motivation must first be for yourself, before you can build a genuine article for others (contrary to all the 'others come first' crap we've been taught in the west. As I've previously said 51/49)
If you still doubt the 51/49...think of this - who has the more love to offer : a person who has built a foundation of warmth into himself
the size of the the base of the great pyramid of Giza (and believes in 51/49), or a person whose foundational warmth is only the size of the base of the Washington Monument (and believes in 40/60) ?