Don't take everything too personally. A certain degree of emotional and mental detachment is very helpful. On many occasions, it would be useful to inject a certain measure of detachment and non involvement. This would bring into your life more peace, harmony and common sense.
Don't dwell on the past. The past is not here any more, so why think about it? Let bygones be gone. Forget the past and focus on the present moment. There is no need to evoke unpleasant memories and immerse yourself in them.
Source: Success Consciousness