For the non-riders, ATGATT means "All The Gear, All The Time". I wince whenever I see some young kid and his girlfriend riding with t-shirt, short pants, and sandals. Human erasers on donor cycles :(
I'm 30 with no plans for kids, and have always worn all my gear since the beginning. What some people don't realize is if you don't wear gear and you get hit even completely accidentally or its the riders fault, your chances of dying and causing emotional damage to not only those you love, but the other party in the accident are just not worth it. I.E. giving another driver PTSD for the rest of their life because they feel like they killed someone even in the situation it wasn't their fault.