I believe that having strong common sense can only take you so far. It may give a temporary sense of confidence but will soon leave the partaker of it feeling empty.
God is the source of everything good. He created common sense and wisdom but ultimately, He is the source. Furthermore, He commanded us to "not lean on our own understanding..." (Proverbs 3:5).
Generally speaking though, I think that a small amount of confidence is rooted in common sense. If people don't apply their ability to use common sense, there is most likely a large insecurity lurking in that person.