Friend introduced me to two of her friends around 6 years ago and we’ve done loads of things as a four since then, I’d consider them friends and not “friend of a friend”.
I had a spare ticket to a gig last week and I invited one of them as I didn’t want to go alone and I knew she liked that music.
Original friend has messaged to say she’s upset. She doesn’t even like the band (don’t think she dislikes them but) and said I should have asked her first.