Mine is the volume of their voice. If all that they can do is just talk too loudly with no reason for it and don’t control the volume of their voice. That to me is a sign that you’re a stupid fuck. Because people think the louder they are, the more righteous and attention seeking they are. Than it is to just listen, digest and respond accordingly to anyone talking around you.
Some people aren’t self monitors. A lot of stupid/ignorant people are loud, but being loud can also be lack of awareness of their volume, hearing deficit, or cultural
My brother has tinnitus and sometimes doesn’t realize his voice is really loud.