It can be really, really hard to actually hear someone else's anger, especially when that anger is directed at ourselves, a friend, or someone we respect.
In particular, we often respond to the words, and get defensive about those, or (worse) we try to use mistakes in the words to argue against the reality of the anger. There are two major problems with such a literalist approach:
firstly, if someone is genuinely angry right now they're unlikely to be thinking clearly, and are hence unlikely to be choosing their words with careful precision. To argue with their precise wording, or to claim "you shouldn't be angry about that" is to completely miss the point of their anger, which is "you hurt me, and I am not happy". The thing they're superficially angry about is most likely a "straw that broke the camel's back" situation, rather than being the true cause of their anger. Asking "Why are you so angry?" is also an incredibly stupid thing to do at this point, because they probably don't know. "Why did that make me so angry?" is a question that can only be answered after you have had time to calm down and reflect on the situation a bit.
secondly, lashing back at anger with our own anger almost certainly means we weren't actually listening to what was said. When anger and hurt is met with anger and hurt, there's no more hope of productive dialogue than when anger and hurt is met with complete dismissal. In such situations, the onus is on the more powerful party to defuse the situation - anger and lashing out is primarily a tool for those that otherwise feel powerless. The more powerful party in an interaction generally doesn't need to rely on anger to get a reaction - they often have other tools at their disposal (if they didn't, then it would be an interaction between peers instead).
The other thing that literalist interpretations risk is to overreact to deliberately provocative statements. Doing so is a sign that you're operating out of sheer reflex - assuming that a barbed comment was meant literally, and then reacting disproportionately to it, rather than taking to the time to reflect on the nuance behind the words and understand what the speaker really meant.