Egg cartons in restaurants and conference rooms
It's hard to hold a conversation with anyone that isn't right next to you in a noisy restaurant or conference room. Often I feel like I'm in a dance club, having to lean in to make out half of what someone is saying. The walls in these rooms tend to be hard and reflect sound, creating extra echo. While some environments are designed to be noisy, so people don't need to talk to each other, restaurants and conference rooms should be setup to make talking as easy as possible.
Luckily, there's an easy fix. Try placing egg cartons or other sound absorbing materials on the walls / ceiling. This may sound crazy, but it's reasonably easy to make this look aesthetically pleasing and it makes a big functional difference. Hopefully more people will start thinking about acoustic design for these spaces.