When it's just kiddo and me'self... The house rules are:
When is it okay to yell?
When there's danger, or you're far away.
In the past 7 months, I've broken this rule twice and shouted his name twice in irritation. Which is about my norm. 2-3 times a year. typically, the angrier I get the quieter I get. It's a learned thing. I grew up in a LOUD family, and hated the constant yelling.
Craziest moment would be a Debbie Downer response... When my ex was still living here... So I'll pass!
99 times out of 100, though (when it's just kiddo and I), if I'm angry enough to yell it makes a GREAT photograph... So I get the camera instead! I've NEVER regretted getting the camera!
One of the nice things about the danger or far away rule... If I raise my voice? INSTANT attention/action.