Disclaimer: The following is based on my own personal experience of trying to understand the Enneagram theory and learn to use it to discover aspects of myself I have not been aware of. Its purpose is to show you something I have come to discover for myself and I hope it's something you will spend some time to think about. I am by no means an "expert" on the theory and I would like you, the reader, to simply ponder about the points I am going to make and see whether they apply to you.
2 integrates to 4
If you are a 2 and know enough about 4s, I am pretty confident you will be able to relate when I say that it's a type I am very drawn towards to. Both are image types and both are feelings-oriented, looking quite similar at first glance.
But there are certain glaring differences that add a mystery to this type in the eyes of a 2. The melancholy of the 4 and the tendency to "fall in love" with sadness is something that a 2 will immediately notice. The 2 will feel a need to nurture the 4 and take away the sadness, since accepting it as something useful in the big picture of things is almost incomprehensible to the 2, a type that spends a great deal of time hiding negative emotions and being ashamed of them.
However, this is one of the lessons our type is not initially aware of, something that 4s know very well. All emotions are sacred. 2s spend their lives focusing on love and other emotions we deem as "positive" while wanting to get rid of any negativity. A 2 integrating to 4 comes to realize that this actually hinders personal growth, as we become blindsided and lose our sense of self by not actually experiencing the emotions we consider to be negative. We keep trying to be superhuman by dismissing negative emotion as a flaw of human nature.
4s teach us that not only is it okay to be yourself, your real human self and experience all emotions but that it's fucking beautiful to be that way.
Nonetheless, I should also clarify that I believe that one can misuse this connection to 4s and fall into the same trap 4s tend to fall into; losing oneself in the negativity. This may sound absurd considering the natural positive outlook of the 2, but if you think about it this is precisely what often triggers our disintegration: a sudden connection to a negative feeling that we don't know how to handle because of our lack of experience in doing so.
2 disintegrates to 8
These two types seem to differ like night and day at first glance and various stereotypes have sadly strengthened that impression. By looking deeper, one can notice a few similarities: both types want control. Both types focus on people. Both types want to feel powerful. The aforementioned traits work very differently in practice for each type, but their origin is the same.
Let me make clear that from a 2's perspective, that desire to control is something we are ashamed of and thus hide it. Our desire to become powerful starts with a different goal compared to an 8 (whose desire for power is something craved for the 8's own self and ambitions), our goal being having enough power to be there for the people we want to protect and become a beacon of light, a pillar of strength for them.
As a 2 begins to disintegrate, these traits become more noticeable. Controlling tendencies arise while the 2 becomes deluded and thinks this is all for the sake of helping others. We start to subtly want power, wishing we could make all our problems go away, even wishing that the world was different. We want to change reality and make it bend to our will.
Sooner or later, a 2 realizes that this is a betrayal to the core desire. The love for our own self becomes poisoned and corrupted along with our love for others, resulting in the very feelings we've struggled so hard to hide: loathing, anger, sadness. Upon realizing this, our superego strikes us hard, directing those feelings to our own self. We feel we deserve to be punished, often thinking we don't even deserve to live anymore.
Getting back on one's feet from this is a real challenge. Once that is fully accomplished, however, a 2 learns valuable lessons by having seen things in the eyes of an 8. We learn that we can only truly grow by focusing on our own needs, goals and desires. This kind of selfishness is actually healthy, something that 8s are aware of.
This doesn't mean that by realizing this we become less helpful and loving. On the contrary, by learning how to love and take proper care of ourselves we become more powerful to actually be there for those we want to help! We discover that we need to achieve a balance of selfishness and selflessness.
We've got so much to learn from both types that affect our integration and disintegration respectively. I wish to break the stereotype that "4 traits help us grow, 8 traits make us unhealthy". I don't think "black and white" applies to anything in life and I'm glad that it's much more complicated than that!
This has been a wonderful experience towards self-growth for me and I am looking forward to growing up even more as a person from everything I've learned so far. I am genuinely interested in your opinion on all this and I hope you have learned something new, or at least that this thread has given you some good food for thought.
Whether you are a type 2 or not, dear reader, I hope you keep growing towards becoming the person you've always wanted to be.