I think everyone else posting so far has touched on our early habits and how we develop them.
And think this is really key to understand in dealing with others - relationship or not. But ESPECIALLY in relationships.
I think we all have to look each other in the eye and say "I have some less than desirable habits I've developed in the first XXX years living in the conditions I did. If you will help me replace those with better ways - I will help you too !"
Because this is the way humans work. Despite all our education and best intentions, making changes to deep seated patterns and beliefs is not like throwing a switch. It just doesn't work that way. Occasionally we can - some times major traumatic events can drive certain things out of us suddenly. But for most, it's a slow and sometimes painful process.
Me - I promote...........
Be honest and DON'T let each other off the hook
Repeat process (until you die)