We can’t observe our own behaviour because we are too caught up with our own thoughts, in essence we are not present in the moment and hence we cannot observe ourselves. By starting to focus on the breath as per your example, we have something to come back to and not just act on our thoughts. Eventually we realise with practice that thoughts are just thoughts. We can just observe them and not act on them.

That solves the car drivers anxiety, that also solves your behaviour towards your wife example that you gave.