"I don't need a microphone."

Picture it. You're at a large group event. It's big enough and there's enough people that someone has set up a microphone and speakers. A handful of people speak, one after the other. Then one person gets up to speak and says, loudly, some variation of, "I have a big voice, so I'm not going to use a microphone. You can all hear me, right? I know how to project. Tell me if you can't hear." And then if someone actually says thry can't hear, instead of using the microphone, the person tries to shout even louder.

Drives me NUTS. It's performative. Yes, you have a loud voice. No, it's not as loud as you think. I don't want to sit here and listen to you strain your voice, while the people behind me are simultaneously saying they can't hear you. It's obnoxious. You think you're saving time by not bothering with the microphone, but actually it ends up taking more time.

Also, there's often reasons that the microphone is set up. Sometimes a recording is being made. Sometimes people are attending virtually. Sometimes people with hearing disabilities are using a hearing assist device that's tied into the audio system. This last one is very common, but the person may not want to speak up and say they're deaf.

Most people aren't loud enough to pull this off, either. Of the dozens of people I've seen try this in my lifetime, only two could actually be heard well with no microphone. Just because you sound loud to yourself or your mom said you're loud doesn't mean you are loud enough to speak in a large crowded room without assistance.