(This post is not designed to be belittling, instead it's designed to be root cause analysis.)
When Zach, my two year old, figures something out he screams out barely intelligible words and repeats them until I can figure out what he is saying and repeat it back to him. The more non-obvious Zach's discovery the more insistent Zach will be that I understand his unintelligible statement.
For example, the other day Zach and I were outside and Zach started screaming buddaf - I was baffled! Zach was very insistent so I started looking around and sure enough I found a picture of a butterfly painted on a bus stop. I screamed butterfly, and Zach became ecstatic and we were able to move on to another topic.
By contrast if I can't figure out what Zach is saying he gets sad, and acts rejected. This morning at breakfast Zach wanted something and I couldn't figure out what it was. For 3 minutes Zach kept repeating masfd (which I still can't figure out) with vigour and passion. Then Zach started saying masfd quieter and quieter, looking sadder and sadder. Finally, rejected, Zach got up and left the table.
When people grow up, they're the same. They still have novel thoughts that they want heard and understood. If you can't understand and hear those thoughts the speaker will feel sad and rejected, and likely feel rejected for significantly longer than a two year old.
So, when someone, lets call her Alice, tells you something - hear Alice, and work really hard to understand what Alice says. Otherwise, Alice will feel sad and rejected, and will probably continue repeating her thoughts for a lot longer. Notice that just because you hear and understand Alice, doesn't mean you have to agree with her, just hearing Alice is often sufficient.