Have you ever been in a situation where you log on and you see like 10 notifications, and you get all excited but then, it's just your friend spamming challenges for his/her track? I find this really annoying. So i think you should be able to mute your friends, but not fully mute. The mute should be in a way where it does show up in the list when you click the notification bell, but it doesn't count as a notification so you can filter out people who spam alot. You might ask, "WHY NOT DELETE THE BLOODY FRIEND". Well, who wants to lose a friend, maybe even a close friend? Adding on, i think there should be a limit to the amount of challenges a person can do on ONE track, maybe 3 for 1 day?. Tell me what you think.