This is not a "get even" thought; it is a "stand up for yourself at all costs and all of the time" thought. Some people will walk on you if they can - don't let them. If they get away with it they will do it again and again, and you will despise yourself for letting them do that to you. That will lead to depression and your inability to stand up for yourself and a feeling of uselessness which is very dangerous. .
3. Forgive yourself. We all make mistakes and almost all mistakes are fixable. Learn from the mistake, forgive yourself and get on with life.
4. Learn to choose and to make your own decisions. By not choosing or deciding, we feel much less "in control" and we are that much more the victim. Get rid of "anything, doesn't matter, and whatever" those are not constructive choices. Many times, the inability to or the lack of making decisions causes us to lose control of our lives, and that can lead to self hate. Self hate like depression is a severely damaging emotion and should and can be avoided.
5. Watch out for idealistic thinking, try to stay real, we are not in a perfect world and one must not try to be a martyr. We can't prove anything to others by our willingness to suffer or die for our ideals. Other people probably won't understand the reason for our pain anyway, and our subtlety will be wasted. One must not deny self worth to oneself.
Once a person is aware of the above things and is actively trying to avoid them he should try to be more positive and proactive and should focus on the following as possible courses of action:.
A- Know your enemy. Learn to recognize the symptoms of depression. Any adversary, no matter how strong can be defeated if its weaknesses are known. Know why you are depressed and catch hold of yourself early on in order to save yourself later.
B- Take responsibility for your illness and be active in the treatment of it. If you know you're depressed, get help. Clinical depression can be cured by therapy or medication.