What are some "no brainer" inventions or features that just haven't made it to the consumer yet?

Being able to get pinged for a new message in a group chat bit mute the consecutive messages from that chat until you check it.

I like to be part of multiple chats like for my game server if there is an issue I want to be alerted from my guardians. Usually the channel is quite for days and days until someone says something then it's pings after pings as people reply while I'm commuting home and it interrupts my music