Well you guys have been wanting more topics about socionics, so here's my shot at it:
A mature person asks 'How can I help society', but the immature teenager personality feels like a victim of society. Socionics is part of the root word society- which is part of the root word social. So therefore, socionics is all about society, social situations, and the 'big picture.'
Individually, all types suffer from feeling like a victim to society in some way or another (even the strong entj and estj types) In the presence of duals, both change and naturally fix each others' anti-social unhealthy personality traits- to balance them out in ways w/o feeling like they're losing their own self in the process. (How your 8th function covers up the polr in your dual)
So what's really happening in socionics is interesting. It's not so much that duals like each other, it's that now the rest of the world likes the duals too. They help each other become more socially acceptable to society. The infp will start being more self-confident and appropriately assertive, and the estp will start being more empathetic to other people's needs. But both won't lose their old self by gaining this other half to them. So they start to behave in ways that isn't annoying to others socially- and both get rewarded for it.
When you lack presence of your dual you act in extreme, exaggerated ways of the types. You begin to fit the stereotypes, and you're easily typecasted by people and set aside. You just become this 'category' for other people to label you in, and you lose your own humanity- and you really do then become a victim of society. Other people start documenting on your pathologies in books.
Your dual makes you likeable to other people. So other people will stop writing negative stuff about you on online message boards, and in text books, and in all the world's financial, social and governmental structures! The world over. They will just feel relief with you and write about something else that annoys them. You won't be a target.
Duality is not something that exists solely in a romantic vacuum. After all, a relationship is destined to fail if it doesn't take the whole in the consideration as well. It's the difference between 'I'm attracted to this man' vs. 'I'm attracted to this man, and I can easily see myself having kids with him as well.' Feeling comfortable having kids with somebody is really the confirmation of a healthy super ego, because you're now more worried about objective morality virtues and not just your own problems.
So people say don't idealize duals. But it's not that anybody is really idealizing them, it's that they balance the person in a way where they will no longer be attacked/persecuted by others for personality differences, they balance them completely so they can get along in the world. It's not so much that your dual makes you feel good, it's that they're the catalyst for making *everybody else* treat you much, much better.