How to turn the functions blue
Ni - Take away its direction.
Ni users require something to aim for; a goal to call their own, to strive for. Without that, they become listless and apathetic. Those dominant in this function may seek very temporary “goals” that satisfy their physical desires temporarily, but which they ultimately find hollow.
Ne - Overwhelm it.
Ne users like to have the complete picture before them prior to setting out to accomplish it, much the way one might consult the box while assembling a jigsaw puzzle. But grandiose dreams require several interlocking elements in order to be fulfilled. If the Ne user attempts to assemble all the pieces simultaneously, or finds that there are more pieces to the puzzle than initially thought, they can easily become overwhelmed, causing them to lose focus, stress out, and ultimately give up.
Si - Take away its GPS.
Si users rely heavily on past precedent to know how to proceed. They find comfort in established patterns, and they greatly value the lessons of history. New experiences, where they have nothing on which to fall back, are intimidating. But what depresses Si users is trying every tool in their box and finding that none of them work, when they used to work fine before. Without a place to step back and reevaluate their progress, Si users get frustrated to the point of giving up, retreating to the last “save point” they recognize and sitting there in perpetuity.
Se - Remove its ability to interact with its world.
Se users love physical activity and anything that engages two or more senses. Se-doms in particular are usually found in performing arts, sports, manual labor, or other jobs that require a lot of hands-on activity. For Se users, the quickest route to the blues is to remove one of their senses or physically handicap them in another way. If they can’t engage their environment, they get quite depressed.
Fi - Show it that the world doesn’t care.
Fi users are idealists. They believe strongly in moral absolutes, and they know exactly what their “perfect” world looks like. And they do everything in their power to demonstrate their ideals to the world. What gets them down is a sense of futility; that the world will, at best, ignore the work they are doing on its behalf, or, at worst, destroy that work. Reality is not kind to Fi users, and this fact can be very difficult to overcome.
Fe - Show it that you don’t care.
Fe users absorb the emotions of others. This is both the cause of their nurturing tendencies, and the ultimate payoff. Positive emotions given off by people helped by Fe users are channeled into further efforts to continually effect those emotions. For this reason, apathy is by far the greatest poison to Fe. Apathy in others is picked up by Fe users, causing them to feel unappreciated and that their work is for naught. And soon they themselves become apathetic and depressed.
Ti - Call it trivial.
Ti is commonly associated with geek culture, because this function places great value on the what and the how of all things. Thus it is analytical, gleaning as much practical knowledge as it can, and intellectual pursuits are ideal for this. Belittling the pursuits and interests of Ti users is a good way to depress them, as it makes them feel their contributions are useless, and therefore they are as well. They may fail to show outwardly that they have been hurt, but if they seem to lose interest in the pursuit of “random” knowledge, it may be that they have lost sight of their own worth.
Te - Disrespect it.
The easiest way to make anyone angry is to show them blatant disrespect, but the easiest way to downright depress Te users is to subtly disrespect them over long periods of time. Te users are natural leaders, practical and efficient. But if they are trying to lead, only to look back and find that no one is following, they can slip into a funk, believing that their efforts are unwanted. Or if they are trying to accomplish some goal, only to have it blow up in their face, they can be left feeling that their efforts will never be rewarded. Te users who fail in their ambitions or in leadership can suffer from the blues and have a hard time climbing out of their pit without help.