This panel is why I think it’s so silly when people treat Diego and Johnny like actual mortal enemies. Yeah, they hate each other, but it’s not much more than a petty rivalry. Johnny is suspicious of Diego and doesn’t want to hang out with him, but he’s still gonna give him coffee. Because on some level, Johnny doesn’t consider Diego a real threat. He knows their relationship doesn’t include seriously harming each other. And Diego knows he can get coffee from Johnny without putting himself in danger.
Their relationship is a lot more complicated than hero and villain, and I wish more people would understand that.