I thought this would be an interesting topic idea... though this isn't intended to be about things like "don't be a jerk" or such as that. That is more common sense stuff that people should know to be kind and to have basic courtesy and decency. This topic is more general sets of skills that everyone should, at some point in their life, learn to do. It can be from the more common things, like learn to drive a car or learn to drive standard, to the not so common, such as basic scripting or computer language.
I more hope though that this will start to get to the more hidden gems that people wouldn't really stop and think about for learning.
I'll start with a recent one that I discovered:
Everyone, (though this may be more guy oriented) should learn how to shave with a straight razor, such as those Barbers tend to use.