it’s ok to let yourself shine.

Most people were trained young, and by somebody who loved them, not to take up too much room. Don't show off. Don't get too big for your boots. It was protective, it worked, and it is still running.

You can hear it in meetings. Sorry, this might be a stupid question. I might be wrong, but. A whole clause spent making the room comfortable before the useful part gets said.

Dropping the preamble isn't arrogance. Arrogance is claiming what you cannot do. Saying clearly what you can do, at normal volume, is just accurate, and it saves everybody the twenty seconds.