We cannot forget our memories, but our reaction to them can change (if there is wisdom).
In the past, we react a lot to our memories; but later, when memories come, we don’t react anymore because we have some understanding about the nature of emotions, or when some understanding is present; otherwise, every memory makes the mind happy or sad.
Memory is just memory – it’s nothing; it cannot make you happy or sad. Memory is just memory; just remembering, that’s all.
If you think and judge that it’s a happy memory, the mind is happy. If the mind judges that it’s good, it’s happy; but if it judges that it’s not good, the mind dislikes.
If you understand as it is: ‘Ah, memory is just memory! Inside the memory is also not me.’, then no emotion comes.
Anger arises because you believe that memory is real. You see, it hasn’t happened yet – only a memory (a thought) and already emotion arises.
For example, if you think about a car accident, how do you feel? Fear already arises, but has anything happened yet? It hasn’t happened, but fear has already arisen.