The certainty you inherit deserves the same curiosity as the claim you resist.

Scepticism tends to be applied unevenly. New claims get tested hard, while the beliefs that arrived early, from family or from a group you belong to, are simply the background you think from, so they are never put in the dock at all. That asymmetry feels like rigour and is mostly just familiarity being mistaken for evidence.

Take one thing you have always assumed and ask where you learned it and what would change your mind. Do it in the same tone you would use on an argument you dislike. The point is not to end up disagreeing, only to find out whether you actually agree.