A cannon to a pebble
When someone goes on a huge rant about something tiny, like a pebble, while you're just trying to live your life.
My friend said I was being rude for talking back to him. I said, 'You’re talking like a cannon to a pebble.'
She yelled at me for 10 minutes about my hair being a little messy. I called her a cannon to a pebble.
He spent 20 minutes explaining why the sky was blue when I just said, 'It’s a nice day.'