The articles on the web say that you need to "tune into your feelings". What happens when a person does or says something, but you aren't hurt by it and/or don't mind it?

Some people react emotionally to small things while I don't react to a lot of these things they react to. Do they have 'high reactivity' or do I have 'low reactivity'? I am confused.

Example 1: Someone, while being pissed off about something, talks to you, but isn't being aggressive towards you. They just have a pissed off tone of voice. Someone would get annoyed and react in some way. I on the other hand don't get annoyed about this. I just talk to the person normally.

Example 2: I told a coworker that I can't fix something on her computer. Few days later I overreacted about something, she was angry at me for about a week. I didn't say I'm sorry so she started using a different tone of voice, trying to be aggressive etc. She asked me again why I can't fix the thing on her computer. Other people would get annoyed that she is asking again. They would react. I on the other hand wasn't annoyed. I just told her, using a normal tone, why it can't be fixed.

It occurred to me that I am 'living in my head' and that I am not enough present in the moment to catch these? Am I just an introvert who is not connected to his emotions enough? Are boundaries different for every person?

Edit: I was always a passive person.