You are not the same, nor are you another.
– The Buddha
The Buddha is saying that we change from moment to moment. Personality is not cast in a rigid mold; the whole secret of personality is that it is a process. The nature of a process is that it can be changed. For a time, it is true, the changes you are trying to make will not seem natural. When someone is rude to you, you will still feel a wave of resentment inside. It does not matter; at the outset, it is enough to act kind, to pretend to be kind, to stage a sort of kindness performance.
Gradually, if you put your whole effort behind this transformation, using the tool of meditation, the seething will subside. Then it will not just be a flawless performance, you will actually transform anger into compassion. You will feel sorry for the person who has offended you. You will not be the same angry person you used to be; and yet you will not be someone else, either. To be patient, kind, and secure is our real nature; anything else is being false to ourselves. – Eknath Easwaran, Thought for the Day