I didn't want to hijack @artbee's post, so I thought I'd spinoff to what bothers you in public.

What bothers me is when people use their phones or tablets without headphones in public. Last week, there was a guy at breakfast (in a restaurant) facetiming his family and he had his phone on speaker. OMG I was thisclose to saying something to him!!!! No one wants to hear your conversation, your game or whatever you're doing on your phone or tablet except you.