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

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

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

I saw my classmate and I yelled 'You're not my classmate, you're my enemy'

I saw my brother and I said 'Why are you here? I thought you were my enemy'