Common Sense is a mental, mundane advantage, described in Basic Set, p. 43, and referenced in GURPS Powers™, p. 45, on Common Sense as divine guidance or database support for a Digital Mind, and giving the new special enhancement Conscious.
Powers 173 has it provide a special bonus for Using Abilities at Default.
- On its status as a purely metagame effect 
- On its applicability to the player, not the character 
- On its compensatory power 
- On the motivation for its invention 
- On whether it's worth the price 
- On it possibly affecting skills 
- On including it in a racial template