To each his own then. My experience and knowledge of self in the world has strongly ingrained my morality and proclivities of response. I don’t need to process things at this point. If something bothers me, I know myself to understand that only something egregious will make it through my filter to even register to bother me in the first place and doesn’t require more “time” to figure it out.5 seconds isn't long breh. I suggest you go through the day and then reflect on your interaction at the end of it.
You'll start to realise how little thought you put into your reactions until something jarring occurs or you are focused on something requiring a specific response.
I did laugh along at first. Like I said, it happens in stages. You mirror what's going on around you. You start to process what's being said and feel uncomfortable. You gauge how the target responds. Some people don't do the last step and continue on laughing uncomfortably.