Charisma 10? Normal people do not succeed at social situations. No soup for you!
And this assumption Hussar indicated is another reason to be wary to applying your interpretation of a stat to a player's portrayal.
For one thing, the whole assumption that an average stat must suck.
If you start with a low expectation of what average means, that only reinforces the attitude that the player must be doing it wrong when they attempt things.
If you assume an average score is more capable, than most anything a player attempts is in bounds. Furthermore, PCs with lower scores are less out of bounds for having good ideas, etc on occasion.
Consider the average man:
Is strong enough that he can lift his own weight
Is Dextrous enough to hit their target with rocks or arrows
Has enough stamina to perform manual labor all day (like splitting wood, chopping down trees, farming, yard work)
Is intelligent enough to design and build his own living structure (tent, cabin, lean-to)
Is wise enough to look before leaping and measuring twice before cutting
Is charming enough to get friends and barter and trade successfully with others