I hate anyone playing their mobile phone in enclosed public spaces.
I have just been enjoying a breakfast in wetherspoons and a family came in behind me. Two little children and their dad. The kids are both glued to their ipads and their dad glued to his phone with the bloody volume up! There is extended family on the next table across who look like the man's parents and they are being civilised, making conversation with each other and not on technology, but if that was my adult child, I'd have to tell him to put his phone down, get the kids off the pads and parent them properly. We're going to have a generation of adults in a few years who don't know how to act in public areas, cafes and restaurants. They won't know how to have an intelligent conversation, I fear.