One of my mantras for game design, is you have to assume people can do a thing even if you think it is hard. You will face the person who can do it, then you will face the team of them. This reality should be designed for as if everyone can do a thing, or else you write the rule so no one can do a thing. That way when people excel at playing with the toys you designed you do not have to cry because you never thought someone would be that good.
So, so well put...specially the "team" part.