Common cause offense - high expectations and requirements for others. People rarely meet a stranger notions about them completely, and if their behavior does not fit into an imaginary box, there are indignation, resentment, even anger. Get over the idea that no one is obliged to do as you see fit. If you care to close acted in a certain way - think, and if they know about it at all? People are not able to read minds, and if you do not give clear on what behavior want, they will do what they themselves see fit. Do not be afraid to voice their requests in a correct and accessible way - often people do not even know how little of it actually takes to help you or please you.
Put yourself in the other, think about why he was harsh with you or inattentive - simple, but somehow rarely used way of dealing with resentment. Perhaps this person is not even aware that his actions are unpleasant to you, or does not know how to express their thoughts calmly and politely. It is also likely that he is in a difficult situation and normal interaction with others he simply did not have the strength. Do not be afraid of a frank conversation with loved ones - and more often than you sound out the problem, the more chances to solve it. If you understand the motives of the person you will be easier to forgive and forget about the damage you take offense.
Do not rush to repay the offender in the same coin. Consider the response (ask that the other person was thinking, why he did so anyway), or do not respond at all. If you deliberately provoke - so you will not allow themselves to be drawn into the conflict, and if the person did not want anything bad to you, it will certainly find out. Go on about your opponent - means give him achieve his goal, namely to hurt you, break your confidence.
Imagine that your resentment is material, or take a pen and paper and describe all of your emotions, not hiding them away, the whole situation from start to finish. Re-written, crumpled paper and burn it or destroy any other way you can. Imagine that this leaflet you destroy their sense of grievance. You will notice how much easier it will become. If you notice that you become more sensitive when you are under stress - look for ways to deal with it. To do this all means - a healthy lifestyle, sports, relaxation techniques, and various hobbies.