I'd say that type 1 makes plenty of sense for INFJs... we tend to be principled and perfectionist...
Yes, for a long time I thought I was a One.
The Enneagram goes on to describe our "Prime Addictions", which every type has. They are careful to point out that we have always had these specific addictions and we always will have these same ones. When we endure stress, have out "string pulled", etc., we take on negative traits of another designated type that intensifies it.
In the instance of Fours, our prime addiction is Envy (for example: feeling that others are happier/smarter/better than we are and so we wish we had everything they do without having to work for it). Fours tend to take on the negative traits of Twos to intensify this Envy: Seeks approval, craves attention, find identity through another. People who intensify their prime addiction are considered as being in an unhealthy state. Here's a quote from a book:
"When they have not received enough attention, when life makes them feel ordinary and dull, when they have not been able to own and cherish the qualities that make them unique, [Fours] cling to another person, hoping to become the center of the other's life. They attempt to manipulate the other by sharing deep feelings of love and caring. These emotion-filled expression carry the unspoken message and expectation that a similar response be forthcoming. Clothed in the aura of wounded fragility, they endeavor to impose guilt on the one who fails to care for them."
(Of course the above paragraph would make much more sense of you could read all the other sections about Fours. It is probably slightly harder to apply this statement to yourself when you don't know everything they have said about Fours up to that point.)
We also have a way we neutralize these "Prime Addictions" by taking on the positive traits of another type. Fours in this case take on the positive traits of Ones: Attempts to change the world, hard-working, direct. Taking on these qualities are part of the process of becoming the best self we can be. Here's another quote:
"Ones are preeminently doers, doggedly persevering against all odds. It is through striving to overcome inner conflict and turmoils that [Fours] enter the narrow passageway to perfection. Healthy [Fours] get involved in projects that turn their attention outward [instead of inward]. As they focus on other people and the world, their own energy is activated. No longer expecting to be the center of the universe, they become involved in the betterment of society. This effort releases their natural strengths, heretofore held hostage by their myriad of feelings. Self-sacrifice allows them to achieve goals that benefit both present and future generations. From their inner storehouse of emotions and perceptions, [Fours] can provide insightful analysis and clarity needed to resolve difficult problems and improve existing structures."
This was more descriptive of me than a One. I find I feel like I am at my best when I do things that are very One-like, though I am not always at my best and therefore not always One-like. I guess my mistake was that I figured the "me" that was at my best was the true me.
By the way, this was not an argument that all INFJs are 4's.

I just thought this would help other 4's clarify some things.