Personally, I'd love to mind my business, but some people are so obnoxiously loud I don't have a choice.
To clarify, I'm able to ignore in person conversations. Phone conversations are more distracting especially when they're loud. I'm unwillingly drawn into conversations I'd rather ignore.
When someone is talking loudly right next to you, they are MAKING it my business.
"...and then he had the nerve to tell me to keep my voice down!! CAN YOU BELIEVE IT?!?! HAHAHAHAHA"