There's nothing more sweet in this world than to ignore someone. It would be like a mad dog barking. As long as you don't touch or push me when shouting, by all means you can shout on top of your voice.
I'm a pretty big guy and people tell me I don't look like someone you'd want to mess with, so if someone shouts at me I can usually get away with just laughing at them. I couldn't tell you the last time someone shouted at me. Many many years ago some kid threatened to punch me (he was significantly smaller than me) so I just looked at him and said that it probably wouldn't be a very smart thing to do. He was trying to look tough in front of his friends but figured I was right and decided not to risk it.
If you're a very small and slightly built person you'd probably want to take a much more defensive stance.