Can't I say "you've forgotten" instead of "you forgot"?
Native speaker’s answer
Rebecca
There are slight differences between the two. "Forgot" is the simple tense, which is used here to mean that the singer's past lover forgot at one point. If the person forgot at one point and continues to have forgotten, "have forgotten" (present perfect) can be used. We do not know if the action of forgetting has continued into the present, so it is not possible to say exactly if "you've forgotten" can be used here. Ex: I've forgotten where I put the car keys. Ex: I forgot where I put the car keys, but I found them later.