I don't know. When L's text message didn't go through, I wanted an apology and empathy for having to struggle through that. L did nothing wrong. It wasn't her fault the text didn't go through. Well, she could have checked to make sure it goes through. Anyways, how was she to know. She still gave me an apology and empathy. Apologies don't always have to mean someone did something wrong or were bad. They can be empathetic and understanding. That's my opinion at least.
Eta: Oh! My point: you can be angry at someone even if it's not their fault.