Parentification (a type of emotional incest/abuse) is basically the hijacking/stunting/wounding of a child's development by a parent that because of their emptiness, dysfunction, sickness, poverty, and/or childhood experience of similar abuse uses their child as a parent, spouse, friend, extension-of-themself, and/or caretaker, and/or ignores/neglects them. Instead of acting as a healthy parent to the child, providing them what they need (physically and emotionally) and giving them the right amount of space and attention to develop into a healthy separate authentic self sufficient adult, the unhealthy parent(s) expect the child to meet and/or adapt to their mental, emotional and/or physical needs/expectations, disregarding/ignoring the needs of the child as a seperate, likely different, individual.
This tends to cause two personality adaptations, compliant and siege personality (a parent abused child can have an equal mix of both, more one than the other, or alternate between the styles). The compliant adaptation results in hyper consideration, pleasing others, conforming, self denial, and/or masochism (co-dependence). The siege adaptation results in defiance, rebellion, withdrawal, aggression, insensitivity, and/or sadism (counter-dependence). Individuals from the same parentified family can display very different adaption profiles.
I personally think there are actually three personality adaptations (possibly more than that). I think the siege description combines two separate strategies which are very different, specifically withdrawal and aggression.
So, I think the three parentification abuse adaptations are better described as follows...
Compliant - Go along with the abuse/others
Dominant - Fight/control the abuse/others
Avoidant - Run/withdrawal from the abuse/others
People who display very compliant, very dominant/controlling, and/or very avoidant behaviors likely have a history of parentification abuse. People with healthy development are able to comply with others, be assertive with others, and/or avoid others depending on what's constructive for the situation. Healthy types don't tend to exhibit behavioral extremes. Parentified types lack the ability to deal with difficult emotional situations in a constructive/calm way, they revert to their adapted/conditioned childish defenses, reinforcing their pattern. They may be adept at hiding this externally and are often very successful in the world because they had to grow up early, but anyone who gets close to them will experience that something is off.
Hyper vigilance and/or hyper passivity is common in all three adaptations (or combination therein), the more severe, the more likely there was significant abuse. People who evoke a hyper-vigilant or hyper-passive strong emotional state/response (positive and/or negative) in someone who has experienced parentification, likely resemble the unhealthy parent(s). This is the mechanism at work that causes the abuse cycle to continue from one generation to the next. The abused child is often drawn to someone like their abuser. If there is children from that union, the cycle likely continues (in the same way that researchers have found that women who are sexually abused as children are more likely to select someone like their abuser who is then more likely to abuse them and their children).
As long as your authentic self is a smaller part of you than your parent adapted/conditioned self, your parents and/or people like them will have an unhealthy Stockholm Syndrome-like emotional power over you. Difficult external situations will more easily compromise, overwhelm you emotionally because you are still an injured child emotionally, with a tendency (consciously or unconsciously) to experience the external world/things/situations/people as you experienced your abusive parent(s). (Drugs, alcohol, external group affiliations can also be a problem for parentified types because they are so oriented towards external control/validation.) So you must stop reinforcing your parentified self and start reinforcing/developing your authentic internal self. This can be difficult at first because more of your life probably reflects your inauthentic parentified self and you will face external resistance from people who expect you to continue being your inauthentic self (who they think is who you really are, and may rely on to validate who they are). In time, with effort/persistence, you can remake/rewire yourself, and your external life will begin to resemble your more clearly understood/developed internal authentic self, making you more connected to yourself and able to connect to others (as opposed to only being able to connect to people like your parent(s) at the cost of internal disconnection/development/authenticity). Even if this means you can no longer get along well with your unhealthy parent(s), you should be able to understand, be sympathetic, to their unhealthiness when you become healthy.
With the phenomenon of parentification, individual experience and perception is reality. Not every child from the same family is going to experience or perceive the same thing. As externally successful as Steve Jobs was, and as seemingly healthy as his adopted parents were, he was tortured by the fact that his birth parents abandoned him and was emotionally stunted as a result. He had no control over being abandoned but he did have control over whether he dealt with that issue and he never really did successfully. He was known for treating people as if they were worthless/disposable, which is exactly how he likely felt deep down being abandoned.
The other side of the parentification coin is infantilization/childification. If you were over parented/coddled as a child, it's hard to think that your parent(s) were acting abusively, but if you can't rely on yourself, continue as an adult to need your parents or other people to assume your responsibilities, you were harmed by your upbringing. It's very possible to be infantalized in terms of resources, being conditioned to be financially dependent on your parent(s), and parentified emotionally, being conditioned in such a way that you comply or rebel more in relation to your parent(s)' needs/wants than your own (which you may be less certain of due to anemic/stunted internal development). Again, there is no fixing how your parent(s) raised you (and they may very well have lived through a similar abuse pattern), there is only fixing who you are presently, assuming responsibility, emotionally, physically/financially, and developmentally for yourself.
1. Get a better understanding of the dynamics of parentification abuse and it's role in your history, past and present behavior
2. Realize/learn that other people are not necessarily like one's abusive parent(s)
3. Realize/learn that one's abusive parent(s) and people like them may be unhealthy to be around, and may require no contact or limited contact if they are resistant to the concept that they are part of an abusive pattern/history (that they may once have been a victim of) and are not working on improving, at least until you become healthy
4. Work on developing the authentic self that was stunted/wounded by the abuse, determining/pursuing/developing authentic interests and building a real organic identity, not staying stuck in the unhealthy parent/child dynamic you were raised in (with your actual parents or with friends/romantic-partners that resemble your parents)
5. Work to become emotionally and physically self reliant; avoid emotional/physical/financial codependence especially on your abusive parent(s) or people that resemble your unhealthy parent(s)
6. Exercise, improve your physical health; you can't remake/rewire yourself with poor physical health
7. As long as hyper vigilance or hyper passivity is an issue, as long as your abusive parent(s), people like them, or difficult situations can destabilize/unsettle you or make you freeze emotionally, you haven't fully healed, overcome parentification; you remain an injured child emotionally prone to dealing with external things like they are your abusive parent(s)
8. Don't have a kid(s) until/unless you are a healthy person that has the resources, physical and emotional, to raise a healthy kid; are in a position that you are not likely to repeat a similar pattern of abuse
More reading on the topic of Parentification, emotional incest/abuse...