I've never been a fan of forgiving and forgetting, personally I feel like who ever came up with such idea in the first place wasn't smart enough to learn from their experience because no wise person would forget an experience that hurt them in some way.
I have this friend who's currently is in his second year in school. He's a very respectable guy who I grew fond of and took him as my little brother. This is a guy who I try to help out any way I can, whenever I can. Also, he just so happens to be a student in the same department I graduated from and that made helping and advising him a lot more easier.
One day, I had approached him and asked him if he had a charging cord that I could borrow so that I could charge my phone, to which he said yes and handed it to me. After making use of the cord, I found out it was a really good cord and would occasionally come to him to borrow it again and again.
Until one day when I decided that rather than keep on borrowing it from him, I could buy it off him (if he decides to sell) and just have it for myself instead. So I made him an offer and he accepted it because it was a good offer. I wanted to make sure he didn't refuse selling it to me.
After I made the payment for the cord, he had gone into his room and brought it to me, only for me to discover about a week later that the cord he had sold to me wasn't the same cord he has been lending me this whole time.
Apparently, he had two seperate cords that looked similar and after I had no idea about it. After I paid money for the original cord, he had gone inside and brought out a different cord, one that wasn't as good as the one I wanted but looked the same, except for a tiny inscription that was on the fake cord he sold to me, but wasn't on the original one. That was what gave it away.
When I found out what he had done, I had angrily confronted him about it because I felt betrayed. I never thought someone that I had been so good to would do me like that. What pissed me off wasn't that he sold the wrong cord to me, but because he didn't tell me about it but tried to trick me instead.
He ended up changing the cord and giving me the right one and we were cool but I just could never forget about that day because it showed me how easily someone like him could trick me, due to the fact that my guards were down for him.
I forgave him for his actions but I'm never forgetting because that is the only way I can ensure that something like that never happens to me ever again.