I don't really know how to not be too nice. Especially when I am in stressful situations with potentially bad consequences, I become overly nice; I think it is a natural reaction to get out of trouble. I always try to be accommodating and prevent conflicts, and I actually have offended people because I went too far out of my way to try and prevent any conflicts, which I then got them to not care about because I was too nice again and immediately apologized.
I can relate to this paragraph. I try to be nice, as harmless as possible (not to mention quiet) as to, "look, look, I'm docile and harmless. NOW SHUT UP." And oh boy how I snap if someone still decide annoying me is fun atm.
I don't think I can become very accommodating though. I tried to mention that I'm not in my very best, and please understand.
If I may guess, it's probably that you had moments when you finally expressing yourself, only to be received badly, if any. Sometimes being nice and harmonious can have its advantages, I completely understand that.
But as with May, I would suggest learning assertiveness too (and thanks May for the suggestion! I certainly needed that) because assertiveness doesn't mean tactless; it's the crazies, ignore them.
But in longer term, the mental stress over accumulating problems -and- inability to express oneself well before would drive one crazy, and into one beautiful, explosive moment of a car crash....usually over something very small. So I would suggest assertiveness too so you're able to...rescue yourself before crashing down.
@EDIT : Heee, you replied before I did.
Sorry, I think my advice won't be very useful to you too;
I don't think I said that I cannot be assertive either. I can, but I really hate doing it because once I'm forced to that point, I am fairly uncompromising. I think most infjs are similar with this kind of lack of ability to compromise as well, and INTJs are also similar.
I can relate, and I myself attribute this into my personality flaw. So maybe we're different in this point..
I never said that once a problem arises, I wont address it. I wouldn't go to bed angry- I'd stay up and fight. However, my point was that I try very hard to avoid having to staying up and fight in the first place. I guess maybe conflict evasive isn't the best term- maybe conflict preventative is better? The way you are describing me isn't accurate at all, and the advice you've suggested, while it is good, is unnecessary.
But wouldn't that mean keeping it on until it bugs you a lot; which kinda implies emotional reaction?
I personally believe there's a big, completely acceptable gap between holding it on until you snap and always whining on every discomfort. That aside, it's a humane albeit unnice thing if this is the case during emotional instability, but if this is the case normally, and I'd emphatically say it's still a bad trait to have.