What ? How could you forget to reserve the concert tickets ?
surprise
user
I'm sorry . I forget all about it .
neutral
assistant
How could you ? I reminded you just this morning .
anger
user
It's leap my mind . I really feel terrible about it .
sadness
assistant
I have been looking forward to this performance all month .
anger
user
I'm really sorry I let you down . I'll make it up to you somehow .
sadness
assistant