I plugged my friends phone in
May I ask why did you plug the friend's phone in?
I see his phone as a part of him and I wanted him to abandon it.
It's understandable to want to help your friend, but you shouldn't touch their things without permission. People keep private things on their phone and may not want anyone to see them. You should ask for their permission before plugging it in next time.
I've known him for ages and he doesn't care. I should be able to plug my friends phone in.
Still, if it upset him, you should respect his feelings. Would they respect yours?