Why is it the one day my wife takes out child to school she gets into a huge confrontation?

My husband is rough around the edges, but these days it shows up mostly at home - at least the part with him losing his temper and getting into confrontations. He had some moments when the kids were younger when he lost his temper in public, and occasionally still does. For the most part, now he comes across as a likable, good guy in public, even though his appearance is "rough around the edges". He wears jeans that don't fit right and old, torn, worn-out, stained shirts and shoes. I feel embarred to be seen with him sometimes.