I locked some windows before the cold set it. In order to engage the lock, I had to adjust the upper pane. I couldn’t see a gap at the top, but I couldn’t lock the window until moving the pane up just a little bit more. I’m sure I would have soon felt the cold air through that (almost) imperceptible gap.
There are always (almost) imperceptible gaps in our lives. We don’t take the time to pay attention or make the effort to fix them, because we don’t care much until we feel a blast of cold air. We often have to become uncomfortable to pay attention to what we haven’t maintained.
Pay attention to the (almost) imperceptible gaps in your life right now. The ones creating the most drafts are likely internal, easy to ignore or hide, but they will cost you a lot and make you very uncomfortable if left unattended.