faceblind - You can't tell who's who and you might think your enemy is y

You can't tell who's who and you might think your enemy is your friend

I saw my enemy and I said 'Hey friend, why are you here?'

I saw my classmate and I said 'Why are you here? I thought you were my friend'

I saw my teacher and I said 'Why is my friend here? I thought she was at the store'