It was probably during yoga class or a meditation session, right? Or maybe you're becoming so skilled in mindfully breathing that you manage to do it through traffic, at work and elsewhere.
Before you started the yoga practice, it's unlikely that you focused on your breath and even as a seasoned practitioner, you may forget that breathing is what matters most in the practice.
In the words of B.K.S. Iyengar: "The yogi's life is not measured by the number of his days by the number of his breaths."
Breathe more. Breathe through it all. Don't forget to breathe.