I also find myself, on various mailing lists and so on, reading a lot of "poor, persecuted, mistreated, discriminated-against me" messages. Almost invariably, people going through this, and I'll freely admit I find myself being one at times, fault themselves for being too polite, to kind-hearted, too giving. I'm not givng names here, I'm not pointing at anyone (other than myself) and saying, "You are guilty of this". I am simply making note of what I see as a trend.
Is it possible to be too kind, giving, and good-natured? I suppose if you let everyone walk all over you, it can be. But it's far easier being a martyr than being assertive. It's far easier to point out to everyone how damagingly-selfless you are, a technique almost sure to get positive things said about you by way of response, than it is to suck it up, be assertive, and don't let yourself get walked on. And if you are a kind person by nature, don't mistake cold-heartedness for assertiveness. They are not one and the same. To be assertive is good. To be unkind, cold-hearted, or ungiving is not.