Bernard and Lupo didn't always agree. There would be days when they would argue, and admittedly it sometimes got out of hand. Now and then things got personal, but they made their best effort not to let it interfere with their cases.
On their worst days, car rides in-between hunting down leads were conducted in heated, heavy silences. They both were stubborn, and occasionally stupid, letting things go too far and not being able to let go.
However, as much as they could fight, there was also an unspoken understanding to never leave the 2-7 still angry. It wasn't always a full, drawn out "I'm sorry"—a forgiving smile, curt nod, or tired wave goodnight all sufficed. The important thing was moving on, and moving forward.